RO Waste

[Mark Grigg]

If you have soft water why are you using RO ? Many people would die to have soft water where you can harden it up to your requirements (4-8dKH). My water is very hard, having come from a chalk aquifer and plants grow monstrously, fish reproduce like rabbits with what comes out my tap.

If going high tech, you will need at least 50% weekly water changes to remove waste organics. If left the organics build up quickly and algae quickly follows. If I miss a water change it is pretty obvious due to BBA appearing as well as green spot algae within a couple of days.

Thanks Ian, I'll get a KH test done as it's a new house but only a few miles away from my previous so should be the same water, I'll also look to increase the water change although not sure if 50% is possible.

With a booster pump, how is it controlled? I'm trying to be as automated as possible, so if it's a manual exercise it won't fit with my plans, if it can detect pressure and will boost when the float valve opens, then it has a chance.
I do have an 11W UV on the system, which I'd hope will assist with algae spores???

 

[Andrew Butler]

There are many people on this forum who adopt all kind of methods so I'm sure more will comment differently.

I'll also look to increase the water change although not sure if 50% is possible

Maybe a planted tank; at least a high tech one isn't right for you then.

If you have a 500L system then a 50% water change can be a chore but you can simplify things.
I have teed into the intake of my filter so the majority of time to drain water out I just turn everything off, connect a hose and open the tee up then use a vacuum to go over the substrate.
If you have a weir this wouldn't work for you but I'm sure you could fashion something to be removable from one of the pipes within your overflow box that then siphons water off and then you could let your filter sock catch debris and pump it out from the sump or plumb things up a bit different and have it divert to a waste somewhere the possibilities are almost endless.
@Zeus. is one person who I know uses something similar to me when topping up and uses a thermostatic mixer to control the temperature of water to top things up so simply plumb one up under a sink and run a hose to your aquarium or go one better and plumb it directly into your sump.

As Ian says why even think about RO if you have soft water already?
I think you might be trying to over complicate something which if you redirected your thoughts and efforts could be a lot simpler in design and more effective.

This is just my opinion from what I know and many others know far more than me.
Andrew

 

[Kitbag]

You can connect a second membrane which takes the waste from the first membrane to reduce the losses. This definitely requires a booster pump though.

 

[ian_m]

With a booster pump, how is it controlled?

The pump box I linked previously to has pressure switch(s) in it. When you close your RO output valve the system pressurises and the pressure switch turns off the pump. Open the RO output valve and pump comes on automatically. It also has a low pressure switch to prevent the pump coming on if the input water supply stops.

If you are using a pump you can fit a second RO membrane (and filter ?) in the waste output to recover more RO water, but costs more as two membranes to replace at service time. 2nd membrane will have a shorter life due to being fed with "dirtier" water. Also will need two valves and top ups into your storage vessel as the two RO feeds are at different pressures.

As Ian says why even think about RO if you have soft water already?
I think you might be trying to over complicate something which if you redirected your thoughts and efforts could be a lot simpler in design and more effective.

Go to you water suppliers web site and see what they estimate your water hardness to be.

Here is mine from the Southern Water website. A dGH of nearly 16, so nearly liquid rock. RO would benefit me if I could be bothered for the faff factor required, probably at 2:1 RO to tap water to bring dKH down to 5 odd would be a fine start. Note that in rest of world (not UK) 16 dGH is classified as very hard. I do have a whole house water softener for showers and baths as without it everything gets covered in scale pretty quickly. Unfortunately house softener water has no place in aquariums as contains sodium.

Remember 50% weekly water change in a large tank is a faff and time consuming, especially the substrate and plant vacuuming required in a larger tank so anything you can do to make things quicker and easier (ie using tap water) is well worth doing. Look what Zeus has done with a thermostatic mixer valve for his 500litre tank.

Below is a picture of the weekly detritus I vacuum out of my tank. I syphon into a 40l plastic tub, before pumping out onto my front lawn.

I also use a water heater to preheat the 90l water I change. Though for years I just used non heated water, no problems, if anything the fish do appear to like to swim in the incoming cold water for some reason.
https://www.ukaps.org/forum/threads/water-change-heater-project.25877/

 

[Kitbag]

I can recommend:

https://www.osmotics.co.uk/pages/Contact-Us.html

The chap there is very helpful and happy to give his advice. He helped me with deciding on my set up.

 

[Edvet]

Below is a picture of the weekly detritus I vacuum out of my tank. I syphon into a 40l plastic tub, before pumping out onto my front lawn.

Why not add the detritus to your lawn? it's plantfood I water my plants with old tankwater too

 

[Kitbag]

My RO waste mixes with rain water in a series of water butts. When the last one starts to get filled the excess goes to top up the pond.

 

[ian_m]

Why not add the detritus to your lawn? it's plantfood I water my plants with old tankwater too

I syphon into a 40l yellow bucket first, so I can see any fish fry that accidentally get syphoned out. Then pump onto front lawn, the whole lot including detritus. I have quite a green front lawn, in fact a circular area that my hosepipe reaches.

 

[HiNtZ]

I'm sure it's been said (didn't read through all the posts) but that is perfectly normal. The waste water carries the large deposits away before passing water through the membrane. Without this run off, the membrane would become clogged and damaged within a day or two.

My RO/DI system produces 75 litres of waste to every 25 litres of fresh made and takes 8 hours on standard mains pressure. It kills me to waste so much water and I tried to use it elsewhere, but the only thing it's good for if you can be bothered is flushing your loo with it. Forget putting it on the garden plants, or drinking it/giving it to animals - it's like liquid rock and can cause serious health problems.

This summer I will be installing a separate water tank in my loft to catch the waste water and use it 100% for my toilet flushes. Yeah I might go through a few ball cocks because of the limescale, but that's a minor.

 

[Mark Grigg]

Ok, here is my report from my local WA. Sorry its quite in-depth, however I'm hoping someone with good knowledge will be able to decide if my RO unit is needed or not?

Analysis Typical Value UK/EU Limit Units
Hardness Level Soft No standard applies
Hardness Clark 2.72 No standard applies Degrees Clark
Hardness French 3.89 No standard applies French Degrees
Hardness German 2.18 No standard applies German Degrees

Other technical data here


Hardness Results
For most analysis, results are from samples taken at random in the water quality zone of your area. In some cases, results are from samples taken from water treatment supply points feeding the zone.
Hardness Level
Value Soft
Standard No standard applies
UK/EU Limit
Hardness Clark
Value 2.72
Standard No standard applies
UK/EU Limit Degrees Clark
Hardness German
Value 2.18
Standard No standard applies
UK/EU Limit German Degrees
Hardness French
Value 3.89
Standard No standard applies
UK/EU Limit French Degrees

Data is for period 01-January-2017 to 31-December-2017
Water Quality Summary Report
For most analysis, results are from samples taken at random in the water quality zone of your area. In some cases, results are from samples taken from water treatment supply points feeding the zone.
1,2-Dichloroethane
Average <0.09
Maximum <0.10
Minimum <0.09
UK/EU Limit 3
Units µg/l
Number of Results 48
Samples above PCV Limit 0
Aldrin
Average <0.002
Maximum <0.002
Minimum <0.001
UK/EU Limit 0.03
Units µg/l
Number of Results 48
Samples above PCV Limit 0
Aluminium
Average <10
Maximum 22
Minimum <5
UK/EU Limit 200
Units µg/l
Number of Results 38
Samples above PCV Limit 0
Ammonium
Average <0.015
Maximum <0.018
Minimum <0.012
UK/EU Limit 0.5
Units mg/l
Number of Results 38
Samples above PCV Limit 0
Antimony
Average <0.04
Maximum 0.05
Minimum <0.04
UK/EU Limit 5
Units µg/l
Number of Results 8
Samples above PCV Limit 0
Arsenic
Average 0.11
Maximum 0.14
Minimum 0.09
UK/EU Limit 10
Units µg/l
Number of Results 8
Samples above PCV Limit 0
Benzene
Average <0.04
Maximum <0.05
Minimum <0.04
UK/EU Limit 1
Units µg/l
Number of Results 48
Samples above PCV Limit 0
Benzo-3,4-Pyrene
Average <0.001
Maximum <0.001
Minimum <0.001
UK/EU Limit 0.01
Units µg/l
Number of Results 8
Samples above PCV Limit 0
Boron
Average <0.015
Maximum <0.015
Minimum <0.012
UK/EU Limit 1
Units mg/l
Number of Results 48
Samples above PCV Limit 0
Bromate
Average 1.17
Maximum 1.48
Minimum 0.94
UK/EU Limit 10
Units µg/l
Number of Results 8
Samples above PCV Limit 0
Cadmium
Average 0.01
Maximum 0.02
Minimum 0.01
UK/EU Limit 5
Units µg/l
Number of Results 8
Samples above PCV Limit 0
Chloride
Average 15.07
Maximum 18.63
Minimum 12.79
UK/EU Limit 250
Units mg/l
Number of Results 48
Samples above PCV Limit 0
Chromium
Average <0.1
Maximum 0.2
Minimum <0.1
UK/EU Limit 50
Units µg/l
Number of Results 8
Samples above PCV Limit 0
Clostridium perfringens
Average 0
Maximum 0
Minimum 0
UK/EU Limit 0
Units No. / 100ml
Number of Results 38
Samples above PCV Limit 0
Coliform Bacteria
Average 0
Maximum 0
Minimum 0
UK/EU Limit 0
Units No. / 100ml
Number of Results 204
Samples above PCV Limit 0
Colony Count After 72 Hours at 22ºC
Average 2
Maximum 77
Minimum 0
UK/EU Limit No abnormal change
Units No. / 100ml
Number of Results 76
Samples above PCV Limit 0
Colour
Average <0.53
Maximum 1.45
Minimum <0.19
UK/EU Limit 20
Units mg/l Pt/Co
Number of Results 76
Samples above PCV Limit 0
Conductivity
Average 127
Maximum 172
Minimum 102
UK/EU Limit 2500
Units µS/cm at 20ºC
Number of Results 38
Samples above PCV Limit 0
Copper
Average 0.0167
Maximum 0.0331
Minimum 0.0017
UK/EU Limit 2
Units mg/l
Number of Results 8
Samples above PCV Limit 0
Cyanide
Average <2
Maximum <2
Minimum <1
UK/EU Limit 50
Units µg/l
Number of Results 48
Samples above PCV Limit 0
Dieldrin
Average <0.002
Maximum <0.003
Minimum <0.002
UK/EU Limit 0.03
Units µg/l
Number of Results 48
Samples above PCV Limit 0
E. coli
Average 0
Maximum 0
Minimum 0
UK/EU Limit 0
Units No. / 100ml
Number of Results 204
Samples above PCV Limit 0
Enterococci
Average 0
Maximum 0
Minimum 0
UK/EU Limit 0
Units No. / 100ml
Number of Results 8
Samples above PCV Limit 0
Fluoride
Average 0.78
Maximum 0.88
Minimum 0.69
UK/EU Limit 1.5
Units mg/l
Number of Results 8
Samples above PCV Limit 0
Free Chlorine
Average 0.28
Maximum 0.56
Minimum 0.05
UK/EU Limit No abnormal change
Units mg/l
Number of Results 204
Samples above PCV Limit 0
Heptachlor
Average <0.002
Maximum <0.002
Minimum <0.001
UK/EU Limit 0.03
Units µg/l
Number of Results 48
Samples above PCV Limit 0
Heptachlor epoxide
Average 0
Maximum 0
Minimum 0
UK/EU Limit 0.03
Units µg/l
Number of Results 48
Samples above PCV Limit 0
Iron
Average <15
Maximum 50
Minimum <10
UK/EU Limit 200
Units µg/l
Number of Results 76
Samples above PCV Limit 0
Lead
Average <0.4
Maximum <0.4
Minimum <0.4
UK/EU Limit 10
Units µg/l
Number of Results 8
Samples above PCV Limit 0
Manganese
Average <1.0
Maximum 1.9
Minimum <0.3
UK/EU Limit 50
Units µg/l
Number of Results 38
Samples above PCV Limit 0
Mercury
Average <0.022
Maximum <0.022
Minimum <0.022
UK/EU Limit 1
Units µg/l
Number of Results 48
Samples above PCV Limit 0
Nickel
Average 1.2
Maximum 1.8
Minimum 0.7
UK/EU Limit 20
Units µg/l
Number of Results 8
Samples above PCV Limit 0
Nitrate
Average 2.76
Maximum 3.35
Minimum 2.19
UK/EU Limit 50
Units mg/l
Number of Results 8
Samples above PCV Limit 0
Nitrite
Average <0.005
Maximum <0.007
Minimum <0.004
UK/EU Limit 0.5
Units mg/l
Number of Results 8
Samples above PCV Limit 0
Nitrite - Nitrate Calculated
Average 0.06
Maximum 0.07
Minimum 0.04
UK/EU Limit <1
Units -
Number of Results 8
Samples above PCV Limit 0
Odour
Average 0
Maximum 0
Minimum 0
UK/EU Limit Acceptable to Customer and no abnormal change
Units Dilution Number
Number of Results 76
Samples above PCV Limit 0
PAH
Average 0
Maximum 0.01
Minimum 0
UK/EU Limit 0.1
Units µg/l
Number of Results 8
Samples above PCV Limit 0
Pesticides Other
Average <0.004
Maximum 0.019
Minimum <0.001
UK/EU Limit 0.1
Units µg/l
Number of Results 4368
Samples above PCV Limit 0
pH
Average 7.98
Maximum 8.98
Minimum 7.31
UK/EU Limit Min 6.5, Max 9.5
Units pH value
Number of Results 76
Samples above PCV Limit 0
Selenium
Average <0.04
Maximum <0.04
Minimum <0.04
UK/EU Limit 10
Units µg/l
Number of Results 8
Samples above PCV Limit 0
Sodium
Average 9.9
Maximum 10.8
Minimum 9.4
UK/EU Limit 200
Units mg/l
Number of Results 8
Samples above PCV Limit 0
Sulphate
Average 21
Maximum 28
Minimum 16
UK/EU Limit 250
Units mg/l
Number of Results 48
Samples above PCV Limit 0
Taste
Average 0
Maximum 0
Minimum 0
UK/EU Limit Acceptable to Customer and no abnormal change
Units Dilution Number
Number of Results 76
Samples above PCV Limit 0
Tetrachloroethene and Trichloroethene
Average 0
Maximum 0
Minimum 0
UK/EU Limit 10
Units µg/l
Number of Results 8
Samples above PCV Limit 0
Tetrachloromethane
Average <0.07
Maximum <0.08
Minimum <0.06
UK/EU Limit 3
Units µg/l
Number of Results 8
Samples above PCV Limit 0
Total Chlorine
Average 0.35
Maximum 0.65
Minimum 0.09
UK/EU Limit No abnormal change
Units mg/l
Number of Results 204
Samples above PCV Limit 0
Total Organic Carbon
Average 1
Maximum 1.5
Minimum 0.8
UK/EU Limit No abnormal change
Units mg/l
Number of Results 48
Samples above PCV Limit 0
Total Pesticides
Average 0.006
Maximum 0.022
Minimum 0
UK/EU Limit 0.5
Units µg/l
Number of Results 47
Samples above PCV Limit 0
Total Trihalomethanes
Average 30.62
Maximum 39.44
Minimum 24.4
UK/EU Limit 100
Units µg/l
Number of Results 8
Samples above PCV Limit 0
Turbidity
Average <0.09
Maximum 0.61
Minimum <0.06
UK/EU Limit 4
Units NTU
Number of Results 76
Samples above PCV Limit 0

 

[Mark Grigg]

PH Test from the tap (mid 7's), and from the RO (early 6)

​

 

[dw1305]

Hi all,

Ok, here is my report from my local WA. Sorry its quite in-depth, however I'm hoping someone with good knowledge will be able to decide if my RO unit is needed or not?

That is pretty good water. You don't need RO.

You can just look at a few parameters:

The conductivity value maximum 172 microS, mean 128 microS, so not very many ions of any description.

It has very limited carbonate hardness (the 2.18 degrees German) and very little NO3 (maximum 3.35 ppm) etc. The pH is high because of the added NaOH (which probably accounts for the 10ppm sodium as well).

cheers Darrel

 

[ian_m]

Analysis Typical Value UK/EU Limit Units
Hardness Level Soft No standard applies

Says it all, almost as good as RO water . You are lucky.

I suspect you have also fallen to the must use a test kit syndrome.
https://www.ukaps.org/forum/threads/what-about-test-kits.52487/
It is unlikely (though might be true) the tap water pH is 6.0. Water companies raise the pH (by adding sodium hydroxide and others) to prevent lead pipes being eaten away. Could be interference due to the chlorine affecting the test kit. Also test kits don't really work, and should be ignored is dKH is below 4, which your water is. Test kit in bin please.

You will need to harden it slightly to get it to maybe 4-8dKH, as your source water "is to die for" soft. Most test kits, pH pens do not work reliably (full stop !!) when water is soft, below 4-8dKH. Making it up to 4-8kDH gives you some buffering capacity to "buffer" pH changes if things start going wrong. (may also make you pH test kit read correctly).

Either use limestone base hardscape, add calcium carbonate, add some limestone sand to your substrate or add reminerlising salts.
http://www.theplantedtank.co.uk/RO.htm
https://www.aquaessentials.co.uk/se...h=544_40_229&zenid=cvajjf7vn112v12os4tsmi1uc5

 

[Mark Grigg]

Says it all, almost as good as RO water . You are lucky.

I suspect you have also fallen to the must use a test kit syndrome.
https://www.ukaps.org/forum/threads/what-about-test-kits.52487/
It is unlikely (though might be true) the tap water pH is 6.0. Water companies raise the pH (by adding sodium hydroxide and others) to prevent lead pipes being eaten away. Could be interference due to the chlorine affecting the test kit. Also test kits don't really work, and should be ignored is dKH is below 4, which your water is. Test kit in bin please.

You will need to harden it slightly to get it to maybe 4-8dKH, as your source water "is to die for" soft. Most test kits, pH pens do not work reliably (full stop !!) when water is soft, below 4-8dKH. Making it up to 4-8kDH gives you some buffering capacity to "buffer" pH changes if things start going wrong. (may also make you pH test kit read correctly).

Either use limestone base hardscape, add calcium carbonate, add some limestone sand to your substrate or add reminerlising salts.
http://www.theplantedtank.co.uk/RO.htm
https://www.aquaessentials.co.uk/se...h=544_40_229&zenid=cvajjf7vn112v12os4tsmi1uc5

Hi all, That is pretty good water. You don't need RO.

You can just look at a few parameters:

The conductivity value maximum 172 microS, mean 128 microS, so not very many ions of any description.

It has very limited carbonate hardness (the 2.18 degrees German) and very little NO3 (maximum 3.35 ppm) etc. The pH is high because of the added NaOH (which probably accounts for the 10ppm sodium as well).

cheers Darrel

God guys I feel a bit of a tool, I thought the RO would give me optimum water to start, however reading this and more research, I've probably created more of a problem for myself Especially I understand the elements that the plants need more now, so it's looking like a switch in strategy now, auto top up from the mains and buffer the tank up. Spare RO for sale

 

[Mark Grigg]

Just a thought here, would there be any benefit to keeping the RO pre filter and carbon filter and bypassing the resin filter to feed the float switch?

 

[ian_m]

Just a thought here, would there be any benefit to keeping the RO pre filter and carbon filter and bypassing the resin filter to feed the float switch?

Yes if it is a dechlorinating pre-filter, though I suspect the allowable flow rate won't be that high (same as RO unit).

You are better with one of these, that will have a decent flow rate.
https://www.osmotics.co.uk/products/2-Stage-Heavy-Metal-Removal-Filter-System-and-Dechlorinator.html

In the end I would just use tap water into large drum (maybe heat) add dechlorinator (add GH booster if you can be bothered) and pump into tank easy. Some people fill containers (say 25l) perched on top of a ladder so they can just syphon into their tank, no pumps needed. KISS Keep It Simple St**id and you will be more likely to do it and do it correctly.

 

[Mark Grigg]

Yes if it is a dechlorinating pre-filter, though I suspect the allowable flow rate won't be that high (same as RO unit).

You are better with one of these, that will have a decent flow rate.
https://www.osmotics.co.uk/products/2-Stage-Heavy-Metal-Removal-Filter-System-and-Dechlorinator.html

In the end I would just use tap water into large drum (maybe heat) add dechlorinator (add GH booster if you can be bothered) and pump into tank easy. Some people fill containers (say 25l) perched on top of a ladder so they can just syphon into their tank, no pumps needed. KISS Keep It Simple St**id and you will be more likely to do it and do it correctly.

Thanks Ian, I think the RO is pretty similar to the one on your link, I've taken the resin cartridge off and filling from the carbon exit, flow is very good, so I've turned it down at the tap. PH is

back to normal.

 

[HiNtZ]

PH Test from the tap (mid 7's), and from the RO (early 6)View attachment 114489​

Give it enough breathing time and that RO PH will work its way up.

Someone I met recently got the bug for tanks and went to the fish shop to ask "what's the best water" - where they gave him 150 litres of RO and he filled the tank with it and dumped the fish/plants in. Didn't say anything to him about how essential at least some minerals are so I topped him up with some GH boost and have a bone to pick with the shop when I go in there.

Anyway, as was said previously..... your water seems just fine. I'm a tad jealous in fact.

 

[Mark Grigg]

Give it enough breathing time and that RO PH will work its way up.

Someone I met recently got the bug for tanks and went to the fish shop to ask "what's the best water" - where they gave him 150 litres of RO and he filled the tank with it and dumped the fish/plants in. Didn't say anything to him about how essential at least some minerals are so I topped him up with some GH boost and have a bone to pick with the shop when I go in there.

Anyway, as was said previously..... your water seems just fine. I'm a tad jealous in fact.

Thanks HiNtZ that's interesting to understand and I'll keep note of that incase my Ph goes the other way.

Tank is now complete, the auto top up is working a treat, 1 x 21ltr change at 12:00 and 1 x 7ltr at 18:00 - 196 litres per week from a 400 litre aquarium (that is a guesstimate). Still needs to clear a bit and a few plants to add as we go. Now the water testing and waiting game begins.