# RO DIY Remineralisation for Low Tech- "dirted" tank



## JMorgan (8 Apr 2016)

I will be slowly converting my existing tanks to a dirt substrate (aquatic soil/peat/red clay) as I am very pleased with how the plants are thriving in the one I have. I'm not remotely "purist" re Natural/Walstad method fish-keeping and perfectly happy to dose the water column if it helps my plants thrive. But I'm not interested in the spectacular growth rates and heavy maintenance associated with Hi-Tech and can't afford the CO2 kit anyway. I provide 24/7 care for my disabled partner and so need to minimise those aspects of the hobby that need larger chunks of time to see through and can't be stopped once started: large volume water changes for example.

I would really appreciate some guidance and advice on how to best approach remineralising RO water to add to soil substrate tanks? Having read James Planted Tank resource on RO water I'm sorry to say I'm still confused, not least because the formula assumes 50% weekly water changes and a hi-tech approach with CO2. Re substrates I assume there's not a big difference between soil/clay substrates and manufacturer nutrient enriched aquasoils like ADA: It's just that HiTech lighting and CO2 will cause plant growth to burn through vastly more nutrients than low tech?

Can I therefore also assume that James' formula is applicable to low tech, but that slower growth means that one might either a) not need to dose the water column or b) dose it relatively very infrequently and perhaps only to top up trace minerals?

What and how much to add to my 100 litre barrel of RO water to get soft and slightly acid water that will be good for shrimp and soft water / blackwater type fish?

James' formula:

0.4g Calcium Chloride Dihydrate
2.0g Calcium Sulphate Dihydrate
2.0g Magnesium Sulphate Heptahydrate
0.7g Potassium Carbonate
per 25 litres Water

So x4 =

1.6g Calcium Chloride Dihydrate
8.0g Calcium Sulphate Dihydrate
8.0g Magnesium Sulphate Heptahydrate
2.8g Potassium Carbonate

per 100 litres of RO water

So this gives a GH of 5 and a KH of 1 about which James states "_The KH is very low as I find some plants seem to thrive with these low levels. As long as your weekly water changes are maintained there shouldn't be any problems with having a very low KH even when injecting CO2._"

So I'm not injecting CO2 and would struggle to do weekly water changes even if it weren't contrary to the principles of the Walstad method to do such large % changes . . .  or is James assuming weekly water changes because he's assuming EI dosing regime (or similar) in conjunction with CO2?

Is there a better formula to work with for a soil substrate tank? Why is it better?

What do these numbers (the amounts of each substance per 25 or 100 litres) mean in terms of TDS as this is often the guideline given for keeping shrimp?

Assuming folks here will help me arrive at a working formula, can I mix everything up in a tub in the right proportions and just dose by the teaspoon? What I mean is, as in EI dosing, how much do the exact amounts really matter? I've read many posts where the point is hammered home that being anal about exact amounts is missing the point of supplying an abundance of nutrients . . . but is it more important to be exact when remineralising and when you don't intend to do regular large water changes?

For example if I did:

2.0g Calcium Chloride Dihydrate
8.0g Calcium Sulphate Dihydrate
8.0g Magnesium Sulphate Heptahydrate
3.0g Potassium Carbonate

And then bunged approx. 20g (or 4 teaspoons) of my mixed together formula into 100 litres how much of a difference would changing those tenths of a gram actually make?

Lastly what would I most easily and safely reduce or increase in order to change the water parameters? Lets say I wanted to keep fish or shrimp that needed slightly harder/ higher pH water or alternatively very very soft/acid water?

Out of interest can anyone comment on what point does providing the optimal water for the animals conflict with providing adequate nutrition for slower growing plants? I ask because a number of the species I'm interested in keeping in future are often (shown on youtube) being bred in quite barren looking tanks with some leaf litter and a few bits of driftwood to mimic the nutrient poor water the species are found in in nature: Does it follow that these species can't be bred/thrive in water that will support healthy (if slow-growing) plants?

Sorry this is so long - I do hope my questions make sense! If you got this far thanks for reading!
Julian

PS Was unsure whether to post this in this sub-forum or the Water Chemistry forum so mods please move if you think appropriate?


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## rebel (9 Apr 2016)

Hiya JMorgan,

This all depends on the actual tank/plants/fish that you plan to keep.

With soil/low tech, you can set it up for 6 monthly water changes and top off with RO water. Feed the fish and enjoy the tank.

btw those measurements don't matter that much TBH.


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## ian_m (9 Apr 2016)

Why not just mix 50:50 RO:tap water (or 30:70 etc) , like a lot of people do, especially if running low tech & dirty tank where water parameters will probably make little difference.


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## dw1305 (9 Apr 2016)

Hi all, 





ian_m said:


> Why not just mix 50:50 RO:tap water (or 30:70 etc) , like a lot of people do, especially if running low tech & dirty tank where water parameters will probably make little difference.


I agree with the others, you probably don't need to re-mineralise your RO water, because you will have bases entering the water from the substrate. 

If you think you need some more hardness, then tap water is often a good source, you can go to your water company's web-site for values. 





rebel said:


> With soil/low tech, you can set it up for 6 monthly water changes and top off with RO water. Feed the fish and enjoy the tank.


 I <"like some water"> changes low tech., but I just change a small volume of water fairly regularly. Because I have soft water fish and hard tap water, I just add about 1/10 tap water and then I aim to keep the tanks at about 80 - 100 ppm TDS. 

The two easiest approaches to fertilizer addition are you can either:

Add a small amount of a total fertiliser on a regular basis (~1/4 - 1/10 EI rate). I would buy a complete mix from <"one of our sponsors">, or
You can use the health of a floating plant as a measure of when to feed (the "<Duckweed Index>").
cheers Darrel


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## JMorgan (11 Apr 2016)

Thanks everyone - really appreciate the advice. The reason I got the RO unit in the first place was that I was told that this area is notorious for pretty extreme fluctuations in nitrate levels. When I was measuring more often than now, my tap water was often above 40ppm nitrate and higher and never once even close to the reported figure from Yorkshire Water, even allowing for a large margin of error. If the consumer test kits were more reliable I'd make a nuisance of myself with Yorkshire water, but they are (with some justification) unlikely to take consumer test results seriously in terms of the legal 50ppm limit. The point is that in order to get stability and be working with something of a known quantity the only option was RO and remineralisation. This is a VERY heavy duty agro-industry area btw. 

That said I do appreciate that if I do 10% to 25% tap water (because I'm mostly interested in soft water fish too) then the nitrate fluctuations will have a minimal impact once the  dilution takes effect. Can I assume given that I've checked there's no chloramines that if I just add the 1/10 tap water and leave it for 24 hours the chlorine will have gassed off? I ask as I'd prefer not to add Prime if its not necessary. Further given that this is a 200 year old farm house that may or may not still have some lead piping buried in the walls, would I be safer just to add a tiny bit of Prime anyway? I'm not concerned about the initial amounts but the build up over time.

If I measure my tap water with my TDS pen and it says (for e.g.) 330ppm if I do 1/10 tap do I end up with 33ppm? Or isn't it that simple?

If 80-100 ppm TDS is good for soft-water fish, and presumably shrimp, what is the upper limit of what is termed "soft"? Are there fish species that thrive/will only breed in less than 50ppm or is it just that they can tolerate it and do perfectly well at higher TDS, just not too high? What about plants? Where can I find an up to date list of plants suitable for soft-water low tech BUT with all the necessary ferts? I ask because I read a very interesting (but also confusing) article by Tom Barr talking about low-tech EI dosing and how plants can transition how they get their CO2 in tanks that _never_ get water changes. Rubisco (sp?) came into it somewhere . . . an enzyme I think? The post was from 2005 but the conclusion was that there was almost nothing that can't be grown so long as you don't mind very slow growth, which was inspiring of course. But thinking might have changed since then . . .?

Calcium 68.5 - mg Ca/l
Magnesium 25 - mg Mg/l
Residual chlorine - free 0.11 - mg/l Cl2
Residual chlorine - total 0.18 - mg/l Cl2
Aluminium 2.9 µg Al/l
Colour 0.7 20 mg/l Pt/Co Scale
Conductivity 517 µS/cm
Fluoride 0.06 1.5 mg F/l
pH (Hydrogen Ion Conc.) 7.59  pH Units
Iron 6.7 µg Fe/l
Nitrate 25.82 mg NO3/l
Nitrite 0.009  mg NO2/l
Sodium 15.7 mg Na/l
Copper 0.0401 2 mg Cu/l
Lead 0.19 10 µg Pb/l

Given the above results from Yorkshire Water for my area and given that I inherited an EI dosing pack with a secondhand tank, how do I use the EI nutrients in tanks that I haven't yet converted to soil but which are still low-tech? Lets say I notice my duckweed begins to look a bit pale or slows down, what would make sense to add as a starting point?

Darrel when you say, "Add 1/4 to 1/10 EI", does that mean that amount of Macro/Micro EI solution five days a week, rest weekends as per standard practice (without the water change), or could I perhaps just bung in the whole or half (or less) the daily amount for the volume of the tank, but just do this once a week? Maybe macro mid-week, trace/micro at weekends for e.g.? I read elsewhere Tom Barr talking about doing small regular doses of ferts in low tech tanks but then just leaving off any dosing for a week or so until the plants noticeably slow down a bit - personally I think that's a touch optimistic for my inexperienced eye, but I think the same idea could much more easily translate into how much or how little duckweed I have to scoop out to stop it taking over completely! I can also easily see the rate at which Frogbit roots re grow after I've trimmed them back . . . 

thanks for all the help


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## ian_m (11 Apr 2016)

JMorgan said:


> I ask as I'd prefer not to add Prime if its not necessary


You should always always always add Prime even with RO water, as an RO unit does not 100% guarantee removal of chlorine or ammonia. If your input filter is not a chlorguard or is "used & exhausted " or is running too fast or you get chloramine in your water, then your RO unit will let chlorine or ammonia (from break down of chloramine) through. Of course, you can do what most fish shops do that supply RO and test your RO water before use. You need to test for free chlorine and ammonia before use.


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## dw1305 (11 Apr 2016)

Hi all,





JMorgan said:


> Darrel when you say, "Add 1/4 to 1/10 EI", does that mean that amount of Macro/Micro EI solution five days a week, rest weekends as per standard practice (without the water change), or could I perhaps just bung in the whole or half (or less) the daily amount for the volume of the tank, but just do this once a week?


 Yes, just add 1/10 etc of the weekly dose for EI once a week. Personally, if I had your tap water, I would just cut the RO with 10% - 20% tap water and see how you get on without adding any fertilisers for a while, my suspicion would be that this will add sufficient nutrients and hardness.





JMorgan said:


> Lets say I notice my duckweed begins to look a bit pale or slows down, what would make sense to add as a starting point?


That will be fine. If your duckweed grows very quickly and is green, it just tells you have enough nutrients and buffering (it doesn't do well at low pH levels). By using a floating plant it takes CO2 levels out of the equation

As soon as your duckweed looks a bit pale, and doesn't grow so quickly, you have run out of a nutrient. The most likely ones to be deficient are nitrogen (N) and/or potassium (K) (the most likely), with magnesium (Mg) and iron (Fe) other likely possibilities. Nitrogen, potassium and magnesium are all mobile within the plant, and the plant will green up pretty quickly when you add the deficient element, but if it is the new leaves that are pale it is likely to be iron (Fe) deficiency, and those leaves won't recover, although the new leaves will be green. 


ian_m said:


> You should always always always add Prime


 It is probably safer, if you buy "Pond Prime" or "Seachem Safe" you get the same product more cheaply. 


JMorgan said:


> If 80-100 ppm TDS is good for soft-water fish, and presumably shrimp, what is the upper limit of what is termed "soft"? Are there fish species that thrive/will only breed in less than 50ppm or is it just that they can tolerate it and do perfectly well at higher TDS, just not too high?


 Black-water fish (_Apistogramma elizabethae, Parotocinclus spp. etc_) are only really happy in very soft, acid water, and definitely need it to breed successfully, but most soft-water fish are fine at 80 - 100 ppm TDS. 

You can breed _Apistogramma borelli, A. cacatuoides, A. "_Blue-Steel_" & A. trifasciata_  in water that is pH7 and ~ 150 ppm TDS.

Shrimp vary between species, Red Cherry Shrimp do very well in hard water, but struggle in soft water.

cheers Darrel


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## JMorgan (12 Apr 2016)

Ian - thanks for the advice. I do add Prime because of lead pipe concern. 

Darrel - Thank you very much - I'll make up a batch of RO and do some TDS measurements as I add the tap.

When changing TDS for stocked tanks what are the recommended increments/timescale with which the TDS is raised or lowered? Presumably softwater species acclimate more readily to lower TDS but I assume the process still needs to be gradual? For eg a tank that's at 275ppm TDS over how long would I get it down to 80-100ppm TDS through partial water changes with pure RO? Just change 10% daily until its right? Or could I go quicker and do an initial 50% change so long as i added the RO very gradually over the course of several hours? I'm trying to strike the right balance between giving the fish the water they prefer asap and changing things too quickly for them.

Going in the opposite direction, I think my daughter's red cherry shrimp will probably be happier in something closer to 100% tap which is going to mean moving them to a shrimp only tank I'll need to set up. The tank they're in now is about 120ppm TDS when it should be closer to 250ppm TDS (I've recently read elsewhere) - so drip acclimate them over several hours or do partial water changes over several days?

thanks again


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## ian_m (12 Apr 2016)

JMorgan said:


> of lead pipe concern


Your RO unit and pre-filter will remove lead if it is present. However in UK lead will not be present (in any amount that will cause issues) as water supplies will be phosphate dosed, so that insoluble lead phosphate is formed in the pipes and lead doesn't pass into the water.


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## dw1305 (12 Apr 2016)

Hi all, 





JMorgan said:


> I think my daughter's red cherry shrimp will probably be happier in something closer to 100% tap which is going to mean moving them to a shrimp only tank I'll need to set up.


You can still use 80:20 etc. RO:tap water, but just add a source of carbonate hardness to the tank.

<"Oyster shell chick grit"> is a good cheap option.

cheers Darrel


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## rebel (13 Apr 2016)

dw1305 said:


> Hi all, You can still use 80:20 etc. RO:tap water, but just add a source of carbonate hardness to the tank.
> 
> <"Oyster shell chick grit"> is a good cheap option.
> 
> cheers Darrel


Hey Darrel, how quickly does the grit dissolve in tanks? Does it continue to dissolve or get covered by biofilm and stop the leeching eventually?


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## JMorgan (13 Apr 2016)

dw1305 said:


> Hi all, You can still use 80:20 etc. RO:tap water, but just add a source of carbonate hardness to the tank.
> 
> <"Oyster shell chick grit"> is a good cheap option.
> 
> cheers Darrel


Thanks Darrel - I'll definitely get some. I'd also like to know how long it takes to have some effect - presumably its going to dissolve quicker in softer water and then slow down over time, but roughly how much per litre to put in for cherry shrimp and how long before the TDS changes level out?

Are those white blocks I've seen for sale for shrimp basically formed calcium carbonate?

many thanks


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## dw1305 (13 Apr 2016)

Hi all,





rebel said:


> how quickly does the grit dissolve in tanks? Does it continue to dissolve or get covered by biofilm and stop the leeching eventually?


It raises dGH/dKH reasonably quickly in soft water, because it is made of shell, and the chick grit is finely ground (giving a large surface area). 

I haven't used it for a while but I think it took about a month for each fragment to dissolve, it would be quicker in softer water. It should just keep on dissolving until the water is fully saturated with HCO3- ions.

I've left some in a relatively small volume of  RO water and it raised the conductivity to about 700 microS (~400 ppm TDS) over a couple of weeks. 

The pH rose from ~pH5 (acid due to the dissolved CO2) to ~pH8 within about an hour (when the conductivity was less than 50 microS) and stayed there until the end of the experiment (which is why pH isn't a very useful measurement on its own).

cheers Darrel


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## dw1305 (13 Apr 2016)

Hi all,





JMorgan said:


> Are those white blocks I've seen for sale for shrimp basically formed calcium carbonate?


Possibly, but I don't know. 

My guess would be a mix of "Plaster of Paris" (calcium sulphate (CaSO4·2H2O)) and chalk dust (calcium carbonate (CaCO3)), that would be easy to set in a mould (and they are two very cheap raw materials).

Cuttlebone (sold for budgies etc.) is an alternative to shell grit, it is pretty spongy and made of aragonite, so it will dissolve even more quickly, and the shrimps may well pick at it.

cheers Darrel


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## rebel (13 Apr 2016)

dw1305 said:


> Hi all,It raises dGH/dKH reasonably quickly in soft water, because it is made of shell, and the chick grit is finely ground (giving a large surface area).
> 
> I haven't used it for a while but I think it took about a month for each fragment to dissolve, it would be quicker in softer water. It should just keep on dissolving until the water is fully saturated with HCO3- ions.
> 
> ...


thanks for this info. I recently sprinkled some into my aquasoil (coral fragments that is) and it seems to have stabilised my kH at 4.


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## JMorgan (13 Apr 2016)

Thanks again Darrel - I love to learn, especially the myth busting stuff that helps me avoid shelling (forgive the pun) out for ridiculously expensive products.

On that subject, if Seachem Prime neutralises nitrites and nitrates as well as ammonia, chlorine and chloramine how or why does it not interfere with the dosing of ferts such as Calcium, Magnesium and Potassium nitrates? If I'm adding tap water to my RO in order (at least in part) to provide these minerals to my plants and then adding Prime how does that mean I'm not back to square one? That must have been asked before so feel free to ignore it - I'll search harder.

More importantly, I've just filled by RO reservoir and added 1/10 tap (12 litres) which brought the TDS up to about 40ppm (so 24 litres tap should be bang on in future). How much of a TDS reduction is safe within one water change for soft-water species? I know shrimp are prone to TDS shock, but the other tanks all have fish species that really like soft and acid . . . I'd just like to be clearer on how to best stage the change so nobody gets stressed (including me!)

cheers


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## dw1305 (13 Apr 2016)

Hi all,





JMorgan said:


> More importantly, I've just filled by RO reservoir and added 1/10 tap (12 litres) which brought the TDS up to about 40ppm (so 24 litres tap should be bang on in future). How much of a TDS reduction is safe within one water change for soft-water species? I know shrimp are prone to TDS shock, but the other tanks all have fish species that really like soft and acid . . . I'd just like to be clearer on how to best stage the change so nobody gets stressed (including me!)


A result. 

I'd just change the water a bit at a time until you arrive at your desired value. 





JMorgan said:


> On that subject, if Seachem Prime neutralises nitrites and nitrates as well as ammonia, chlorine and chloramine how or why does it not interfere with the dosing of ferts such as Calcium, Magnesium and Potassium nitrates? If I'm adding tap water to my RO in order (at least in part) to provide these minerals to my plants and then adding Prime how does that mean I'm not back to square one?


No, Prime works in a funny way, it just binds the nitrogen compounds, but they will become available again in a never ending loop. It won't effect the other nutrients. 

cheers Darrel


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