# Do water changes cause co2 fluctuation?



## Niall (30 Nov 2019)

I do a 50% water change every Sunday evening during the co2 and lighting period. Is this bad practice? I have some different algae issues that I am trying to get to the root cause of. Some point in the direction of co2 fluctuation, could this water change be counted as a fluctuation? Should I not inject co2 on water change day?


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## Fisher2007 (30 Nov 2019)

Good question.  I do water changes during the lighting period too and wondered how about the CO2 swing and potential ph swing would affect the tank and livestock.  Fortunately I've not experienced any algae issues that I think may be linked though

Be interested to hear what other peoples thoughts are


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## MJQMJQ (1 Dec 2019)

Niall said:


> I do a 50% water change every Sunday evening during the co2 and lighting period. Is this bad practice? I have some different algae issues that I am trying to get to the root cause of. Some point in the direction of co2 fluctuation, could this water change be counted as a fluctuation? Should I not inject co2 on water change day?


What algae do u have?Got a picture of yr tank?As well as any params that u have.Changing water will reduce co2 temporarily.


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## Zeus. (1 Dec 2019)

Doing a WC during the CO2 period will cause a fluctuation in CO2 on that day which may help to the precipitation of algae issues. Not having the CO2 on on WC day would only make the fluctuation worse.

I always do my WC before CO2 on to avoid these fluctuations and will even delay the start of CO2 on and lighting etc if I need more time ( Delaying CO2 on and lightning is a PITA for most folk but with My PLC and @ian_m tankymytank software makes it very easy to do so I do use it from time to time)

Is it causing the algae issues is a tricky one to confirm and a lot will depend on lots of other things eg like the amount of DOC in your tank also. Also places like Aquarium Garden and Green Aqua also do there WC during the photo/CO2 period as they do it when they are open OFC. So the potential of issues is obviously tank dependant.

I would try to avoid WC during CO2 period if you can but if you cant do it late in the Photo period.

Couple of useful Quotes of Clives 



ceg4048 said:


> we know that when the plant senses that high concentrations of CO2 is available, it responds by reducing the production of expensive Rubisco. When it senses a lower CO2 concentration it must increase Rubisco production, however because this protein is so complicated and heavy, the increased production requires 2-3 weeks in order to change the density in the leaf to match the new gas concentration level. So it is much easier to reduce production than it is to increase production. When increasing gas injection therefore, it hardly takes any time to see an improvement in health. When lowering the concentration, the plant will suffer because it must now ramp up Rubisco production to account for the loss of CO2 availability.
> 
> When increasing the light, the plant must reallocate resources from Rubisco production/maintenance in order to deal with the increased radiation. This may entail new pigment production for protection. When the light is reduced, the plant then reallocates the light gathering proteins and can devote them to Rubisco production/maintenance.
> 
> So when we mess around with light and gas, we have some degree of predictability.





ceg4048 said:


> What I mean is that if you are struggling with CO2 stability, or are having difficulty keeping high concentrations, then it's best to focus efforts on the first half of the photoperiod and not worry so much about the second half. If you are running very strong lighting then you are really pushing the plants and it's necessary to have the CO2 going. After 4 hours, if you turn the gas off, the water stays saturated for a couple of hours after the valve closes and the concentration trails off. So if you have an 8 hour photoperiod and you turn the gas on 2 hours before lights on, you can turn the gas off after 6 hours. So the gas is still running for 8 hours but it's on-off cycle is offset by the amount of time you turn it on prior to lights on.
> 
> There is no need to run the gas for 10 hours therefore.
> 
> ...



Clive isnt talking about WC but we can use the information and relate it to the WC also. The CO2 flucuation would be transient (assuming your CO2 is normally stable!) So avoiding the first 4-5 hours of photoperiod would be my recommendation as the plants would have had there fill of CO2 so less chance of causing issues


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## Niall (1 Dec 2019)

MJQMJQ said:


> What algae do u have?Got a picture of yr tank?As well as any params that u have.Changing water will reduce co2 temporarily.



I have cladophora, green thread, green spot, bba and hair algae.
It's 50 litres
Twinstar 600S running 65% on 7 hrs plus 30 mins ramp up and down.
Filter is oase biomaster thermo 250 with Seachem media and puragen 
Co2 is on 3hrs before light and off 1 hr before, getting 1ish ph drop
Using ei ferts as per instructions with water change on rest day
Kh is 6
Ppm is high due to ei ferts
0 ammonia 
0 nitrite
Nitrates are about 10mg/l


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## Niall (1 Dec 2019)

I'll put up pics when lights come on.


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## MJQMJQ (1 Dec 2019)

Niall said:


> I have cladophora, green thread, green spot, bba and hair algae.
> It's 50 litres
> Twinstar 600S running 65% on 7 hrs plus 30 mins ramp up and down.
> Filter is oase biomaster thermo 250 with Seachem media and puragen
> ...


How planted is yr tank and how much co2 are u injecting?


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## Niall (1 Dec 2019)




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## Niall (1 Dec 2019)

My drop checker is lime green with a ph drop of 1ish. I am going to do a ph profile today and post it up.


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## Niall (1 Dec 2019)

One thing that has just occurred to me. I replaced my co2 reg 1 week ago because my old one would never shut off completely. When it was off it would still let through 1 bubble every 7 or 8 seconds. Since my new one is installed my algae is much worse. I have read about having co2 on before daylight does anyone do this? My tank does get daylight but it is not beside a window.


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## Zeus. (1 Dec 2019)

Well it is normal to get the full pH drop before lights on OFC which normally takes 2-3 hrs, but natural daylight is tricky. I sheild my tank with hardboard on one and a cardboard cover on the other to the sides that get natural light


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## Niall (1 Dec 2019)

Zeus. said:


> Well it is normal to get the full pH drop before lights on OFC which normally takes 2-3 hrs, but natural daylight is tricky. I sheild my tank with hardboard on one and a cardboard cover on the other to the sides that get natural light



My room isn't particularly bright and the tank is pushed into an alcove with 10cm gap around the tank so the 3 sides are quite shaded.


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## john dory (1 Dec 2019)

Just noticed your co2 bubbles are going straight up.


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## Zeus. (1 Dec 2019)

john dory said:


> Just noticed your co2 bubbles are going straight up.



Think filter was off for Pic 



Niall said:


> My room isn't particularly bright and the tank is pushed into an alcove with 10cm gap around the tank so the 3 sides are quite shaded.



any light level algae will use and thrive so no light is best option when when lights are off


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## Niall (1 Dec 2019)

john dory said:


> Just noticed your co2 bubbles are going straight up.



My filter was off for the photo, I have a co2art inline diffuser on the way to help with distribution.


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## john dory (1 Dec 2019)

Ah


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## Niall (1 Dec 2019)

Some photos now lights are on


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## Niall (1 Dec 2019)

This is my ph profile so far today and I don't think it looks too good. I'm not even getting a  1ph drop with co2 on 3 hrs before lights. Would an inline diffuser help with this or will that only help with distribution?

12pm 6.8
1pm   6.8 co2 on
2pm   6.5
3pm   6.3
3.30pm  6.2  light ramp on
4pm   6.1  light on full intensity 65%
5pm   6.1
6pm   6.0
7pm   6.0
8pm   6.0
9pm   6.0

Lights will be off at 11.30pm with ramp down starting at 11pm.


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## dw1305 (1 Dec 2019)

Hi all,





Niall said:


>


Do the plants really look that pale? If they do, it suggests you may have an iron (Fe) deficiency. Iron is difficult to <"keep in solution">. 

You may have hard water in Dublin, if it comes from a limestone aquifer? or very soft water (if it comes from the Wicklow mountains). Iron deficiencies are much more likely in hard water. 





Niall said:


> Using ei ferts as per instructions with water change on rest day


Does that include <"magnesium">?

cheers Darrel


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## Niall (1 Dec 2019)

dw1305 said:


> Hi all,Do the plants really look that pale? If they do, it suggests you may have an iron deficiency. You may have hard water in Dublin, if it comes from an aquifer? or very soft water if it comes from the Wicklow mountains. Iron deficiencies are more likely in hard water. Does that include magnesium?
> 
> cheers Darrel



Hi that plant is nesaea gold so that the leaf colour. Although if you look closely the new leafs are deformed, I'm not sure why. 
My water is not too hard in my area.
Yes the ei ferts contains magnesium.


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## dw1305 (1 Dec 2019)

Hi all, 





Niall said:


> Hi that plant is nesaea gold so that the leaf colour. Although if you look closely the new leafs are deformed, I'm not sure why.


Not sure then. 

Has the _Rotala _grown better in the past? Its new leaves looks a bit pale as well. 

cheers Darrel


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## Niall (1 Dec 2019)

Yes growth has slowed down and some do look paler now that I look back at older photos.
You think iron deficiency?


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## Zeus. (1 Dec 2019)

There is quite a bit of algae on glass of tank, lily pies and thermometer  Tank needs a good clean IMO, Turkey blasting the substrate and then remove the worse affect leaves a few WCs Big ones then clean the filter media, your pH profile doesnt look too bad at all and flow seems good going of the bubbles swirling round

Your MC isnt looking very good under the carpet and the hair grass also has dead ends






Heres a pic of mine below carpet





and thats 50cm below water.

What ferts are you using ?

I would reduce light intensity and tank clean to reduce DOC

Block off the natural sunlight with bespoke shield


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## Niall (1 Dec 2019)

Zeus. said:


> There is quite a bit of algae on glass of tank, lily pies and thermometer  Tank needs a good clean IMO, Turkey blasting the substrate and then remove the worse affect leaves a few WCs Big ones then clean the filter media, your pH profile doesnt look too bad at all and flow seems good going of the bubbles swirling round
> 
> Your MC isnt looking very good under the carpet and the hair grass also has dead ends
> 
> ...



Hi I know the tank looks bad and you might not believe me but it was no where near this a week ago, there was zero algae in tge lily pipes and the thermometer. I'm just back from a week away. I am using ei ferts that someone threw in when I bought a few bits second hand so I have no idea how old they are etc. 
Yes the monte Carlo and hair grass has never looked so bad. Also deformed leafs on plants and crypts melting.
I have invested in a biomaster thermo and twinstar S and the tank is looking worse now!
Argh  it's very annoying. 
I would like to get my ph drop done before lights on but I'm at my limit with my fish.


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## Niall (1 Dec 2019)

Oh and a clean is on the cards for tomorrow .


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## Zeus. (1 Dec 2019)

All it takes is for the tank to get direct sunlight for a few hours for a few days, which can happen very easy at this time of the year as sun doesnt get very high. 
If the CO2 is off when the sun hits the tank........
I believe you but think you would benefit from a sheild esp when going away


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## MJQMJQ (2 Dec 2019)

Niall said:


> Hi I know the tank looks bad and you might not believe me but it was no where near this a week ago, there was zero algae in tge lily pipes and the thermometer. I'm just back from a week away. I am using ei ferts that someone threw in when I bought a few bits second hand so I have no idea how old they are etc.
> Yes the monte Carlo and hair grass has never looked so bad. Also deformed leafs on plants and crypts melting.
> I have invested in a biomaster thermo and twinstar S and the tank is looking worse now!
> Argh  it's very annoying.
> I would like to get my ph drop done before lights on but I'm at my limit with my fish.


Have u added ferts already?Clean, and add ferts. Also rmb yr water changes and there might be too much P left hence the algae.


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## Niall (2 Dec 2019)

MJQMJQ said:


> Have u added ferts already?Clean, and add ferts. Also rmb yr water changes and there might be too much P left hence the algae.



I have been using ferts for a few months now. I change 50% weekly.


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## Edvet (2 Dec 2019)

Zeus. said:


> So avoiding the first 4-5 hours of photoperiod would be my recommendation


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## MJQMJQ (2 Dec 2019)

Niall said:


> I have been using ferts for a few months now. I change 50% weekly.



Did you increase accordingly to the increase in plant mass?


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## Tim Harrison (2 Dec 2019)

I think that if a system is well balanced it shouldn't really make a difference when you do the weekly water change. Whether the tank is low or high energy shouldn't make a difference either.
Looking at your plants, if it were my tank I'd be looking at the CO2 flow and distribution a bit more closely, and ensuring it was on point.

I might also be tempted to increase the fertz dosing as well. I wouldn't complicate matters trying to guess which fert is deficient, I never do, I just up the dose of the lot, it's far easier and simpler, it's what EI was designed for. That is assuming your fertz are okay, but since you didn't mix them you will never know for sure. Maybe it'd be an idea to bin them and mix your own.


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## PARAGUAY (2 Dec 2019)

As just a hobbyist (but learned about)that's what I do increase fertiliser rather than dwell on what's going on too much. Fertiliser to suit as well at the moment it's the EA The aquascaper, any of the family can dose this simply if l am not about. Having soft water GH booster on WC days.


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## MJQMJQ (2 Dec 2019)

Tim Harrison said:


> I think that if a system is well balanced it shouldn't really make a difference when you do the weekly water change. Whether the tank is low or high energy shouldn't make a difference either.
> Looking at your plants, if it were my tank I'd be looking at the CO2 flow and distribution a bit more closely, and ensuring it was on point.
> 
> I might also be tempted to increase the fertz dosing as well. I wouldn't complicate matters trying to guess which fert is deficient, I never do, I just up the dose of the lot, it's far easier and simpler, it's what EI was designed for. That is assuming your fertz are okay, but since you didn't mix them you will never know for sure. Maybe it'd be an idea to bin them and mix your own.


Agreed some salts are better in terms of solubility etc.Might wanna make yr own one but since the algae issue only popped up a week ago while you went away it appears the plants may have depleted the ferts and the leftover ferts would have contributed to algae.


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## Zeus. (2 Dec 2019)

Tim Harrison said:


> I think that if a system is well balanced it shouldn't really make a difference when you do the weekly water change.



Yes 100% agree hence AG and GA get away with it  But without experience how you dont know if it well balanced . I always plan my WC around non CO2 times.


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## Tim Harrison (2 Dec 2019)

Haha, good point  But to put it a another way, I doubt that when water changes are made makes much of a difference either way.
And if a planted tank is experiencing problems it's probably something else that's the root cause.
In this case probably CO2 flow and distribution and maybe fertz deficiency 



Zeus. said:


> I always plan my WC around non CO2 times.


Despite what I wrote above, so do I. It just makes sense not to waste CO2 if you can help it.


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## dw1305 (2 Dec 2019)

Hi all, 





Niall said:


> I am using ei ferts that someone threw in when I bought a few bits second hand so I have no idea how old they are etc.


You don't need to worry, it won't make any difference for dry salts like KNO3 and MgSO4.7H2O, they don't have a sell by date, and are basically good <"for all of eternity">. 





Niall said:


> some do look paler now that I look back at older photos.
> You think iron deficiency?


It could be, if the new leaves look small and pale? then it is likely to be iron deficiency. Iron is different from most other nutrients because it isn't mobile within the plant so deficiencies show up in new, rather than old, leaves. 

It looks like _Rotala_ spp. are fairly good <"canaries"> for iron deficiencies. 





Tim Harrison said:


> I wouldn't complicate matters trying to guess which fert is deficient, I never do, I just up the dose of the lot, it's far easier and simpler, it's what EI was designed for.


Sound advice.

cheers Darrel


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## Niall (2 Dec 2019)

Tim Harrison said:


> I think that if a system is well balanced it shouldn't really make a difference when you do the weekly water change. Whether the tank is low or high energy shouldn't make a difference either.
> Looking at your plants, if it were my tank I'd be looking at the CO2 flow and distribution a bit more closely, and ensuring it was on point.
> 
> I might also be tempted to increase the fertz dosing as well. I wouldn't complicate matters trying to guess which fert is deficient, I never do, I just up the dose of the lot, it's far easier and simpler, it's what EI was designed for. That is assuming your fertz are okay, but since you didn't mix them you will never know for sure. Maybe it'd be an idea to bin them and mix your own.



I have a co2 art inline diffuser on the way. I had someone fertilizing whole I was away, I think it has gotten worse since I got a new co2 reg. The old one would never turn completely off, when co2 was off it would still let through a bubble every 7 or 8 seconds. I just got the individual bags of ei, I have mixed myself. I think I am over thinking with the ferts being old etc.


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## Niall (2 Dec 2019)

MJQMJQ said:


> Did you increase accordingly to the increase in plant mass?



It has always been planted that way, so I just follow the guide of 10ml per 50litres.


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## MJQMJQ (2 Dec 2019)

Niall said:


> It has always been planted that way, so I just follow the guide of 10ml per 50litres.


Do u have a drop checker to calculate how much co2 u have?If yr plant mass has increased it would be sensible to inject more co2 as well as dose more ferts?


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## Niall (2 Dec 2019)

MJQMJQ said:


> Do u have a drop checker to calculate how much co2 u have?If yr plant mass has increased it would be sensible to inject more co2 as well as dose more ferts?



Yes the drop checker is lime green, any more co2 and my fish start to gasp, I'm on the limit.


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## Niall (2 Dec 2019)

I think I will up fert and many do 70% wc.


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## Zeus. (2 Dec 2019)

Niall said:


> Yes the drop checker is lime green, any more co2 and my fish start to gasp, I'm on the limit



Depends on fish and how long you have had them, Ive had my DC passed yellow and nearly clear at times and my fish was fine


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## Siege (2 Dec 2019)

I like Darrell answer above.

Also consider oxygen. Your outlet looks large and low in the tank. Do you have any surface ripple. 

Wouldn’t automatically consider that a cause for green spot algae but just something that stood out!


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## MJQMJQ (3 Dec 2019)

Fish are more tolerant of high co2 than shrimps but TDS will affect dissolved oxygen and hence gasping?Higher tds means less dissolved oxygen and i think co2 too.As a general guide harder to keep fish will be more sensitive due to the ph drop caused by co2 and perhaps other factors.


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## dw1305 (3 Dec 2019)

Hi all, 





MJQMJQ said:


> Higher tds means less dissolved oxygen and i think co2 too.


It does, but you can ignore it in freshwater. It is relevant for marine fish keepers, where you have much higher levels of dissolved salts. 

The same applies to air pressure, the differences are relatively minor, unless you live in <"Denver"> etc.  

Temperature is the thing that really makes a difference to the levels of dissolved gases, which is why fish from cool, flowing water may struggle to survive even in a well designed system as temperature rises.  




 
cheers Darrel


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## MJQMJQ (3 Dec 2019)

dw1305 said:


> Hi all, It does, but you can ignore it in freshwater. It is relevant for marine fish keepers, where you have much higher levels of dissolved salts.
> 
> The same applies to air pressure, the differences are relatively minor, unless you live in <"Denver"> etc.
> 
> ...


Agreed only farms and high intensity breeders would bother that much in freshwater systems.But then again when the water is too cold the respiration rate of fish drops hence the excess oxygen is useless and too hot the increased respiration worsens the low oxygen situation.


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## Niall (3 Dec 2019)

Siege said:


> I like Darrell answer above.
> 
> Also consider oxygen. Your outlet looks large and low in the tank. Do you have any surface ripple.
> 
> Wouldn’t automatically consider that a cause for green spot algae but just something that stood out!



I run an oxygen pump at night. 
Anyone know what the best duration for this?


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## Niall (3 Dec 2019)

So I went about removing all hardscape and deep cleaning last night. It didn't go well at all. I now understand why people start fresh when cladophora sets in. My carpet was an extremely dense mat of cladophora. Reading that spot treatment and blackouts don't work on cladophora especially when it's established, I removed the carpet altogether. I then took out every plant and manually removed cladophora and affected leaves. This reduced my plant mass greatly. I cut my crypts back completely. I'm not too happy with the hardscape now but on the other hand I almost gave up completely during it. So the rock at the back left will be moved or removed I can't decide yet. I also have 
Sagittaria Subulata Tissue Culture - Tropica 1-2 Grow
Helanthium tenellum 'Green' - Tropica 1-2 Grow
Hydrocotyle tripartita 'Japan' Tropica 1-2 Grow on the way for a new carpet.
I'm not sure I'll ever buy anything apart from lab grown plants again I'm suspicious about where the cladophora came from.
I know everything I cut back will grow in again but I'm disgusted with the whole thing to be honest. I wasn't going to put up a picture but sure here we go.
Btw drop checker is blue because I literally just put it back in and pipes are not yet cleaned because my inline diffuser will be here tomorrow so I will clean it then.


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## MJQMJQ (4 Dec 2019)

Niall said:


> So I went about removing all hardscape and deep cleaning last night. It didn't go well at all. I now understand why people start fresh when cladophora sets in. My carpet was an extremely dense mat of cladophora. Reading that spot treatment and blackouts don't work on cladophora especially when it's established, I removed the carpet altogether. I then took out every plant and manually removed cladophora and affected leaves. This reduced my plant mass greatly. I cut my crypts back completely. I'm not too happy with the hardscape now but on the other hand I almost gave up completely during it. So the rock at the back left will be moved or removed I can't decide yet. I also have
> Sagittaria Subulata Tissue Culture - Tropica 1-2 Grow
> Helanthium tenellum 'Green' - Tropica 1-2 Grow
> Hydrocotyle tripartita 'Japan' Tropica 1-2 Grow on the way for a new carpet.
> ...



Tropica plants are one of the best.However if they are kept too long they can turn unhealthy(yellow).Tap water does contain algae spores.Ideal conditions will make them flourish.Your tank looks clean and nice again though.


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