# Topping up open tank



## jameson_uk (23 Jan 2019)

I currently have a little breeding box that is a bit like a HOB on my Juwel tank.  This means the front flap on the lid is open a little and I have been surprised by the amount of water I have lost to evaporation.

I am considering an open tank in the front room and was wondering about evaporation.  As I understand it, only the water evaporates leaving behind all the minerals etc.   So if I replace the evaporated water with tap water my GH would slowly but consistently rise?

I see lots of posts on shrimp forums about only topping off with RO but haven't really seen this mentioned on aquascaping forums.

Is this something I need to consider or just top up with tap water and don't worry?


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## Edvet (23 Jan 2019)

Technically you would have to use RO water not to influence it.
However through adding EI ferts and doing waterchanges you will be adjusting all the time and get to some kind of balance.
Plants will be using minerals too.  (It''s not the Dead sea................., yet )


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## tam (23 Jan 2019)

I top off with RO, but I don't do 50% weekly water changes and I have it kicking about anyway. I think low tech and open top is perhaps a less common combination? If you were doing low tech smaller/infrequent water changes might be worth looking at RO or bottled water with a low TDS. Or atleast using a TDS pen to keep half an eye on it. What you're keeping, what your tap water is like, water changes, and how long you keep a tank running etc. probably all factor into whether it's an actual issue or a theoretical one.


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## sciencefiction (23 Jan 2019)

My tanks are all open top. I have more evaporation in the winter than in the summer due to the temperature difference. I never top up. I just do the weekly water change and in my case the water level never goes down too within a week for the tank not to function although it can go down substantially.  I've gone on holidays from 2 to 3 weeks and the tanks have managed....When I come back the outlets may be splashing on top of the surface due to loss of water but extra oxygen exchange is no harm when one is away. I have also set up my tanks in a way that they can take the reduced water level.

If you are planning not to do water changes on a weekly basis, which I don't recommend for the sake of the fish, then RO water is probably best. Regardless, I personally find it hard to convince myself that dilution is an alternative to removal. 

On a side note, open top tanks are best due to the possibility of growing emersed plants, which has a major positive effect on the water quality and mineral buildup due to evaporation or anything else is not easily achieved when you have a mass of plants that have access to aerial CO2 growing like crazy.


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## Andrew Butler (24 Jan 2019)

jameson_uk said:


> I currently have a little breeding box that is a bit like a HOB on my Juwel tank.  This means the front flap on the lid is open a little and I have been surprised by the amount of water I have lost to evaporation.
> 
> I am considering an open tank in the front room and was wondering about evaporation.  As I understand it, only the water evaporates leaving behind all the minerals etc.   So if I replace the evaporated water with tap water my GH would slowly but consistently rise?
> 
> ...



On my Aquascaper 900 which is 200L and I lose around 10L of water weekly.
I do use an AutoAqua Smart ATO micro with a water container underneath my aquarium that keeps things topped up for me.
http://www.autoaqua.com.tw/en/sato-120p.html 
I was always sceptical about optical sensors alone so used a Tunze Osmolator on my marine as it was hidden out of the way in my sump but when it came to an open top with external filter this wasn't going to work. I haven't had a problem in over 2 years with the AutoAqua's and there have been 3 running in the house. Keep the sensor clean and you're good to go in my opinion. They have gone up quite a bit since I brought mine though! 
https://www.tunze.com/en.html?user_tunzeprod_pi1[predid]=-infoxunter036

Personally I've never had a problem apart from when I removed an ATO when moving some things around; the water level dropping over the week was a lot more than you think and was quite unattractive to look at.


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## sciencefiction (24 Jan 2019)

Andrew Butler said:


> the water level dropping over the week was a lot more than you think and was quite unattractive to look at.



Yes, it is unattractive to look at and it tends to have some sort of psychological effect on one's brain, guilt perhaps...for it is time to do a water change. At least that's what my head concludes every time. Doing a water change when the level is too low is better than topping up until one gets around to doing a water change. Alternatively, keep the tank lid on.


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## Andrew Butler (24 Jan 2019)

sciencefiction said:


> Yes, it is unattractive to look at and it tends to have some sort of psychological effect on one's brain, guilt perhaps...for it is time to do a water change. At least that's what my head concludes every time.


That 9L (about how much I lose weekly) on an EA aquascaper 900 is around 20mm which to me is a lot and does have that psychological effect on my brain but I think that's OCD 
.9 x .5 x .02m LxWxH = .009 / 9L (not taking glass into account I know)
I accept that's over the whole week but even over 2 days that's nearly 6mm which my eyes spot 
If you're going for a rimless aquarium I think that nice consistent water level of 12-15mm (maybe even a bit less ) below the top of the glass is the whole reason to; surely? - especially if your aquarium is (almost) perfectly level - water doesn't lie afterall.



sciencefiction said:


> Doing a water change when the level is too low is better than topping up until one gets around to doing a water change.


After reading my response do you understand what I'm saying?
I usually do a WC every 7 days which is my aim but sometimes more often and sometimes it will slip to day 8 or 9 but that's unfortunately out of my control


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## Oldguy (24 Jan 2019)

jameson_uk said:


> surprised by the amount of water I have lost to evaporation


Over time topping up with tap water will increase TDS. However as stated above with weekly water changes or there abouts and  extraction of minerals by plants there will be little impact on TDS. Do you still have very soft Brummy water. I used to live just outside Birmingham's water supply area and had liquid rock from South Staffs water. I use rain water its free, RO water is for the steam iron.

Thought about open top tanks but always concerned about fish jumping out and high room humidity from evaporation. Surprised by evaporational loses even from a closed tank.


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## dw1305 (24 Jan 2019)

Hi all,





Oldguy said:


> Surprised by evaporational loses even from a closed tank.


My wife already blames the house plants for the condensation in the house, if I went for open-topped tanks I'd definitely be homeless.

I think some of the differences people find depends on how warm your house is, but you get more water loss in the winter, even from closed tanks. 

We don't have our house as warm as a lot of people do, so we start off with a larger differential between tank and room temperature, which increases water loss. 

There is also the differential in humidity between the air immediately above the water surface (fully saturated) and the humidity of the air in the room. 

When cool, damp air comes into the house, via open windows and doors, it warms and the relative humidity falls. There is a really useful <"relative humidity calculator"> on the Lenntech web site. 

I put 5oC and 100%RH as the outside temperature/humidity and 23oC as the internal temperature. The 100% saturated air coming in contains 5.74 g/kg of H2O, but by the time it has warmed up to 23oC it is only 33% saturated, and could potentially hold 17.6g/kg of H2O.  

As soon as you get some temperature variation, or if you don't have good double glazing, that is a lot of condensation on the windows.

cheers Darrel


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## zozo (24 Jan 2019)

dw1305 said:


> Hi all,My wife already blames the house plants for the condensation in the house, if I went for open-topped tanks I'd definitely be homeless.
> 
> I think some of the differences people find depends on how warm your house is, but you get more water loss in the winter, even from closed tanks.
> 
> ...



I guess the biggest issue is the todays (re)building standard, everybody is pushed/subsidised to make a house as energy sufficient as possible. This means living in a sealed off as possible invironmet with a minimum of draft and thus a minimum of ventialtion. Than depending on the region lots of peoplle prefer it air conditioned and than we end up with the same story, air conditionng only works energy sufficient with a minimum of ventilation. Conditioning are is actualy recycling air in a sealed of invironment and refresh with x %/h. No wonder it needs filters. And no wonder lots of office workers in conditioned building spread a flew like wild fire.

If warm and moist air has no where to go than it can do only one thing and that is condense in the invironment on cool surfaces.

Than indeed having such a modern standardized draftless house, than open top tanks are not a good idea.

I'm lucky i live rented in a house dated from 1920 and even with double glazing and all closed in the winter it still drafts like crazy. I don't realy mind i have 3 open top tanks and never a single drop of condense water on the windows and everything is dry to the bone.. And with all 3 tanks i top off about 2 to 3 litres daily.

I monitored the air humidity for a while about 3 cm above the water level.. I actualy was surprised that it never raised over 50% during lights on.. It must come down again to draft and ventilation also from the warmth the lights above it produce a rising air column above the tank.. I have trouble to keep emersed mosses moist that are higher than 2 cm above the water surface.


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## tiger15 (24 Jan 2019)

Modern tight homes have worst indoor air quality.  Toxic chemicals from building material, furniture and household chemicals can build up to levels that cause sick home syndrome. A remedy is to open windows slightly, vent heavily after returning home away for a few days, and don’t store toxic chemicals such as left over paint, paint thinner and other volatile organics inside the house.

My big tanks are all covered with glass top to prevent fish from jumping out, so evporation is reduced significantly but not eliminated.  I never top them on purpose because I do large water change weekly anyway so tds and kH remain stable.  One advantage of having a glass top is that it conserves CO2 I put in as the cover promotes redistribution and redissolving of escaped CO2 in the air space contained by the cover.

My shrimp bowls that I hanged by the window are open top, and I didn’t do any WC for months, just top with tap water as water evaporates away fast.  The tds has gone up from 150 to 300, and kH from 4 to 7 in 6 months.  I blamed on my shrimp gradual died off to lack of WC and mineral accumulation.  Plants are supposed to reduce tds, kH and GH by taking up minerals  but apparently my plant growth is too slow to catch up with the evaporation.


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## jameson_uk (24 Jan 2019)

Oldguy said:


> Over time topping up with tap water will increase TDS. However as stated above with weekly water changes or there abouts and  extraction of minerals by plants there will be little impact on TDS. Do you still have very soft Brummy water. I used to live just outside Birmingham's water supply area and had liquid rock from South Staffs water. I use rain water its free, RO water is for the steam iron.
> 
> Thought about open top tanks but always concerned about fish jumping out and high room humidity from evaporation. Surprised by evaporational loses even from a closed tank.


No, I live about as far North as you can get and still be classed as Birmingham.  My water is reasonably hard South Staffs water (GH12 / KH5) but I believe it also has a lot of farm run off so is pretty high in nitrates.

I get that plants will use some of what is in the water but surely, even with weekly 50% water changes, everything will constantly rise?  Most people here seem to tear down their tanks every few years which probably means no issues but what about after 5/10 years?

Luckily (?) my house is old, damp and leaky but the heating is set to a balmy 19°C when we are in and is setup to not let things drop below 14°C (which was only as a result of having a tank heater fail on me)


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## sciencefiction (24 Jan 2019)

Andrew Butler said:


> After reading my response do you understand what I'm saying?
> I usually do a WC every 7 days which is my aim but sometimes more often and sometimes it will slip to day 8 or 9 but that's unfortunately out of my contr



After reading your initial post, no, but after reading this one yes.



jameson_uk said:


> I get that plants will use some of what is in the water but surely, even with weekly 50% water changes, everything will constantly rise? Most people here seem to tear down their tanks every few years which probably means no issues but what about after 5/10 years?



TDS meter is handy to keep the tank measure in close range to the tap measure. Sufficient water changes will help with that and the tank can run "healthy" theoretically forever,open or closed.



zozo said:


> And no wonder lots of office workers in conditioned building spread a flew like wild fire.



Through the air conditioning vents at work I can smell what they cook in the canteen, when they've used chemicals somewhere to clean, and it all blows right in my face...In my previous job I sat right under a very dirty grill and I used to get sick every two months. I was saying to a friend recently that there will be time when air conditioning and closed environment such as the current offices will be ruled illegal one day....



dw1305 said:


> When cool, damp air comes into the house, via open windows and doors, it warms and the relative humidity falls. There is a really useful <"relative humidity calculator"> on the Lenntech web site.



I keep my fish room window slightly open at all times. In the summer wide open. It helps with the humidity although its not energy efficient. I also like having a bit of fresh air.


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## HiNtZ (24 Jan 2019)

jameson_uk said:


> I have been surprised by the amount of water I have lost to evaporation.



I lose close to 4 litres a day in the height of summer in my 150 open top. I'm more concerned about the fact there are two pop bottles of water floating around my house invisibly.


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## dw1305 (25 Jan 2019)

Hi all, 





sciencefiction said:


> I keep my fish room window slightly open at all times. In the summer wide open. It helps with the humidity although its not energy efficient. I also like having a bit of fresh air.


We do the same, I can't remember the exact figure (half a litre?) but each human in a house breathes out quite a lot of water vapour every day even without the contribution of plants and fish-tanks.

cheers Darrel


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## zozo (25 Jan 2019)

dw1305 said:


> each human in a house breathes out quite a lot of water vapour every day even without the contribution of plants and fish-tanks.



Tina Turner once sang a song about that..  If i remeber correctly it isn't a song about coocking aplle pie nor about open top fish tanks.


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## Tim Harrison (25 Jan 2019)

I guess condensation etc aside the most important question is, how does it affect our health? 
My tank is in the study and if the door has been closed for a while the moisture in the air is palpable.


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## Andrew Butler (25 Jan 2019)

Tim Harrison said:


> I guess condensation etc aside the most important question is, how does it affect our health?


my guess is less than walking through a car park and breathing in all those lovely fumes?!


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## zozo (25 Jan 2019)

Air humidity between 70-90% is afaik deemed most healthy invironment.. Pretty difficult to reach this as a constant without condensation.
Condensation as we know by itself is distilled water, nothing unhealthy about that.  It is no ventilation and what stays with it is the killer in the end..


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## Edvet (25 Jan 2019)

I remember having big rotary humidifiers in our living room during winter, to keep humidity up.
I later repurposed those to keep my greenhouse humid enough for my orchids................


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## ian_m (25 Jan 2019)

jameson_uk said:


> I get that plants will use some of what is in the water but surely, even with weekly 50% water changes, everything will constantly rise?


Yes it does rise and no it doesn't rise to unlimited. Over time it rises to a limit.

Use this calculator to see what your dose "accumulates" to.
https://rotalabutterfly.com/accumulation-calculator.php

Here is 7.5ppm dosing alternate days with 50% weekly water changes accumulates to average 50ppm (insignificant) over many days.


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## Tim Harrison (25 Jan 2019)

Edvet said:


> I later repurposed those to keep my greenhouse humid enough for my orchids


I would have liked to see that Ed, shame your collection was lost due to a heating malfunction.


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## Oldguy (25 Jan 2019)

jameson_uk said:


> but what about after 5/10 years?


I cut my tap water with rain water to reduce TDS. My planted tank has been running for over 10yrs. Try to match the TDS of the tank water to that of my tap water.  Do about 30+% weekly water changes and run medium high tech with low fish stock.


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## dw1305 (25 Jan 2019)

Hi all,





zozo said:


> Air humidity between 70-90% is afaik deemed most healthy invironment..





Edvet said:


> I remember having big rotary humidifiers in our living room during winter, to keep humidity up.
> I later repurposed those to keep my greenhouse humid enough for my orchids.......


I don't like the air too dry in the house, and I hate it when you go into a glasshouse and the air is drier than it should be. 

That is my abiding memory of the tropical biome at the Eden Project is that the air was much drier than it should have been. It was a warm day and a lot of the plants were showing transpiration and spider mite damage, even with the waterfall etc. The glasshouse is equipped with misters, but they were only on intermittently. 

It was an organised educational visit and I asked afterwards about the humidity, and  they said they kept it at a level that was "_comfortable for the visitors_", because a lot of people found "_hot and humid_" uncomfortable. 

At that point, whatever they might claim about their scientific remit, for me it stopped being anything but a tourist attraction.

cheers Darrel


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## Oldguy (25 Jan 2019)

dw1305 said:


> "_hot and humid_" uncomfortable.


Reminds me of a now deceased old school independent lfs. He ran more than two hundred large open topped tanks in a large space heated room. Specs always steam up when you went inside and the carpet runners between the racks of tanks squelched as you walked on them. Good fish though, but you could taste the air. Always thought I should wear Wellies when spending my pocket money at his shop.



dw1305 said:


> organised educational visit


Have you thought about Bristol Botanical Gardens. Wife & I used to be members but we found it more cost effective to be paying day visitors.


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## Tim Harrison (25 Jan 2019)

dw1305 said:


> At that point, whatever they might claim about their scientific remit, for me it stopped being anything but a tourist attraction.


Last time I visited a couple of years ago the Tropical Biome was looking a bit shabby and the plants were not in the best of shape.
It's become a victim of its own success and is really more of a tourist trap now; wall to wall people doing the Eden Shuffle around the Tropical Biome 
It's a shame, when it first opened it was fantastic.


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## dw1305 (25 Jan 2019)

Hi all, 





Oldguy said:


> Have you thought about Bristol Botanical Gardens.


I used to be a friend, and we took the students there when it was still at Bracken House (Leigh Woods end of the suspension bridge), but I've never actually been to its present incarnation (by the Halls of Residence in Stoke Bishop), and I really should visit. 

We go to <"RBG Kew now">, in the mean time we went to <"National Botanic Garden of Wales">, but it was a long way and we had a couple of horrendous traffic days on the bridge / M4. 

cheers Darrel


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## zozo (25 Jan 2019)

Tim Harrison said:


> Eden Shuffle



What's that? Something like the Harlem Shake?? But than Botanical...


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## PARAGUAY (25 Jan 2019)

zozo said:


> I guess the biggest issue is the todays (re)building standard, everybody is pushed/subsidised to make a house as energy sufficient as possible. This means living in a sealed off as possible invironmet with a minimum of draft and thus a minimum of ventialtion. Than depending on the region lots of peoplle prefer it air conditioned and than we end up with the same story, air conditionng only works energy sufficient with a minimum of ventilation. Conditioning are is actualy recycling air in a sealed of invironment and refresh with x %/h. No wonder it needs filters. And no wonder lots of office workers in conditioned building spread a flew like wild fire.
> 
> If warm and moist air has no where to go than it can do only one thing and that is condense in the invironment on cool surfaces.
> 
> ...


This problem of over insulating probably came to light 80s and 90s when loft insulation grants were pushed by goverments and local authority. Insulation pushed right into the roof eaves instead of a gap were the wall cavity is,resulting in mould in the bedrooms underneath.


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## zozo (25 Jan 2019)

PARAGUAY said:


> This problem of over insulating probably came to light 80s and 90s when loft insulation grants were pushed by goverments and local authority. Insulation pushed right into the roof eaves instead of a gap were the wall cavity is,resulting in mould in the bedrooms underneath.



Today it seems still very hot..  In my country it is.. Houses get an Energy Label nowadays.. Than if you want to sell it, this label reflects in it's value.




I guess mine is closer to G..  I think such an A house all doors and windows closed could be called Hermetosphere..  Good for Wabi Kusa tho..


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## Oldguy (25 Jan 2019)

zozo said:


> Houses get an Energy Label


Same in the UK. The daftest of things can effect your rating. By law a property can only be offered for sale if it has an energy rating. God only knows how my present home would be rated, it was built in 1485. 

Like my Avatar? He was my old guy, died last January.


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## ian_m (25 Jan 2019)

Oldguy said:


> God only knows how my present home would be rated, it was built in 1485.


My mate sold his 1930's house, with I think a B energy rating. He had double glazing, condensing boiler, loft insulation, floorboard sealing downstairs (breathable membrane ?) and when was re-plastered was done with insulated plaster board on exterior walls.


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## Tim Harrison (25 Jan 2019)

Building regs are becoming increasingly stringent when it comes to insulation. The last two houses I've lived in have been new, and apparently not far off passive house standards.


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## dw1305 (25 Jan 2019)

Hi all, 





zozo said:


> Good for Wabi Kusa tho..


I like that, might be a unique selling point. I'm not intending to move, but I'm pretty sure our house's EPC rating would be C or lower.

cheers Darrel


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## Oldguy (25 Jan 2019)

Tim Harrison said:


> Building regs


Building Regs & Listing are often at loggerheads. Thank God the modern 16th century extension put in a chimney and an upstairs. Wouldn't swap for a modern house though could be tempted by an Art Deco house.


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## dw1305 (25 Jan 2019)

Hi all,





Oldguy said:


> Art Deco house


<"Coleton Fishacre">? Not sure the National Trust will sell it.

cheers Darrel


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## Tim Harrison (25 Jan 2019)

Or there is Stoneywell, an Arts and Crafts (not quite Art Deco but lovely nonetheless) house on a slightly more modest scale...


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## Oldguy (25 Jan 2019)

Tim Harrison said:


> Stoneywell &[QUOTE="dw1305, post: 549816, member: 484Coleton Fishacre
> Know them both. Both fabulous in there own way and both small enough to live in, assuming that you have your own printing press. As I don't, I think that I will stay put. Our house though small on the inside (2ft thick walls) is big enough when I vac it.


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## PARAGUAY (28 Jan 2019)

Oldguy said:


> Same in the UK. The daftest of things can effect your rating. By law a property can only be offered for sale if it has an energy rating. God only knows how my present home would be rated, it was built in 1485.
> 
> Like my Avatar? He was my old guy, died last January.


We just lost in 18months our two cats the younger cat passed away first aged 18 we think his mother Soot must have been just under 20 died a few months ago. Funny still look at the fav places , were they chilled out thinking have they really gone


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## Oldguy (29 Jan 2019)

PARAGUAY said:


> We just lost in 18months our two cats


Know what you mean, heart melting when you look at photos. Big hole to fill. Ours was a rescue cat. Came very ill but he pulled through, plastic melting vets fees. With us for seven very happy years. Bomb proof, he would lift his legs so that you could vac under him. Now have another Siamese, a re-homer, one year old queen, very skittish and shy.  Hoping that she will calm down with pheromone vaporizers. Makes fish keeping seem trouble free, well almost.


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## Parablennius (29 Jan 2019)

Tim Harrison said:


> Building regs are becoming increasingly stringent when it comes to insulation. The last two houses I've lived in have been new, and apparently not far off passive house standards.


When we extended our bungalow upwards, because we altered outline and capacity, we had to comply with all kinds of regs including insultion and ventilation. Result is that the triangular voids on three sides are so well ventilated that it blows like a hurricane through there and in winter the voids are so cold that ceilings of the rooms below get condensation on the outer perimeters but we had comply to get the work passed off by the council planners and that was 20 yrs ago. Also, since having cavity wall insulation, the double glazing has now become the cooler surface so they get condensation on now! My 220L nett open tank can use up to 2 Litres per day.


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