# Water Changes and EI dosing



## Jaap (7 Feb 2015)

Hi,

for both practical and educational purposes how does dosing EI and water changes go when:

1. Water changes are made daily?
2. Water changes are made twice a week?

Also, when doing a water change is it better to change as much of the water possible rather than 50? I mean doesn't 90% water change kill bacteria if adding non treated water?

Thanks


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## tim (7 Feb 2015)

My approach if doing daily water changes is to dose macro and micro on alternate days as normal but seven days a week instead of five, I generally carry out water changes twice weekly anyway and I've always dosed macro after waterchange and followed on from there. As for the untreated water question I have no idea as I always use dechlorinator but I've not had issues carrying out upto 90% waterchanges daily when I have algae troubles.


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## Jaap (7 Feb 2015)

So if someone does daily water changes of 90% would it go something like this?
Day 1: Water change add macros
Day 2: Water change add micros
Day 3: Water change add macros
Day 4: Water change add micros
Day 5: Water change add macros
Day 6: Water change add micros
Day 7: Rest day


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## tim (7 Feb 2015)

That would work fine.


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## Julian (7 Feb 2015)

90% water changes every day seems excessive...


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## Jaap (7 Feb 2015)

Maybe not 90 lets say 70 but its still alot...and maybe not daily but every 2 days....the daily was for educational purposes...


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## sanj (7 Feb 2015)

Most Bacteria is not in the water column, it is in the filter media and hardsurfaces, large treated water changes should not have any significant impact on bacterial populations.


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## Julian (7 Feb 2015)

sanj said:


> Most Bacteria is not in the water column, it is in the filter media and hardsurfaces, large treated water changes should not have any significant impact on bacterial populations.



Unless you have chlorine/chloramine in your water.


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## Jose (7 Feb 2015)

I would do a max of 1 wc every 2 days.  So:
Day 1: wc and macro dosing
Day 2: Mmicros
Day 3=Day 1
Etc.
this way you have a minimum of nutrients in the water. You can always dose more e.g 2x EI.


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## tam (7 Feb 2015)

Do yo have fish/shrimp in there? If so would say it depends on the consistency of your water, if it doesn't vary much or your are mixing it up to exact spec then big water changes probably don't matter, if it does vary then smaller changes mean you aren't making dramatic changes to conditions. It might be worth adding the next lot of ferts to the water your are putting back in rather than to the tank afterwards too. Ferts can effect the TDS a lot, so going from EI full water to 'clean' water may be a big TDS change.


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## EnderUK (7 Feb 2015)

I did a big 80% water change today, simply take your time, refill over a couple of hours. When I rescape I do 60-80% daily water changes with fish and inverts in the tank for a week, then every other day, then a couple of times a week. You're fish won't care and the bacteria sure as hell won't care. You can dose your macros and traces at the same time, I've never seen precipitation of iron phosphate and I dose macros and traces at the same time. I guess if you were double or triple dosing then you might get precipitation.


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## Jose (7 Feb 2015)

Ender uk, you might not see the precipitation happening. Its a salt but it might be quite sparse in your aquarium.


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## EnderUK (7 Feb 2015)

Jose said:


> Ender uk, you might not see the precipitation happening. Its a salt but it might be quite sparse in your aquarium.



I have a daily dosing bottle for my nano tank that has iron and phosphate mixed in the same bottle, no precipitation though that's very low ppm for a low tech tank, still probably higher ppm then what's in my high tech tank. You tend not to mix the EI solutions together as the the solutions have much greater ppm in them than what's in your tank. Worst case if it does precipitate in your tank then it will break down over time and slow release the nutrients in the substrate. If you really concerned then add the salts 15 minutes apart.


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## sanj (8 Feb 2015)

Julian said:


> Unless you have chlorine/chloramine in your water.



Yes, although I did say treated water changes, by which I meant treated for such.


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## ian_m (9 Feb 2015)

EnderUK said:


> no precipitation though


It does react and precipitates out as a ultra fine powder that stays in suspension. People have mixed potassium phosphate measured phosphate level and added micro powder and proved phosphate level drops. I have been meaning to repeat this test, but need to use RO or distilled water ie adding 4ml EI dose to 10l water to get 2ppm (I seem to remember), but will require too much RO or distilled water for me to try.



EnderUK said:


> Worst case if it does precipitate in your tank then it will break down over time and slow release the nutrients in the substrate


Don't think so. It gets removed completely from the nutrient cycle, which is why it is such an issue. There is plenty of phosphate in normal outdoor soil, but most of it in inaccessible to plants. Actually not quite true, acid can bring it back into solution, not sure tank and/or plants reach this level to achieve this.


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## parotet (9 Feb 2015)

Hi all

I add every morning both macros and micros and I have very hard water (GH 21 and KH11-14 depending on the season). I have never noticed precipitation or growth problems related to micros (actually my problems have always been related with CO2, flow, too much organic waste in the tank, etc.)... The only thing I do is to make my micro ferts' solution with DI water to avoid Fe precipitation. I've read here in UKAPS that Fe and other elements' precipitation depend on pH but that not all the molecules are affected, it is a curve and depending on the pH a larger % of them are affected... (am i wrong?), thus one option is to assume that this will happen and dose twice the amount, as I do with my micros.

Jordi


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## ian_m (9 Feb 2015)

parotet said:


> read here in UKAPS that Fe and other elements' precipitation depend on pH but that not all the molecules are affected, it is a curve and depending on the pH a larger % of them are affected... (am i wrong?),


I'sh. Its to do with chelation. If solution is acid the iron stay chelated in solution and unavailable to react with the phosphate.

Here ascorbic acid is used to keep the iron chelated.
http://www.theplantedtank.co.uk/allinone.htm

In the tank the pH isn't so low (hopefully) so the iron starts being freed into solution over 24 hours or so, becoming available to the plants or to react with the phosphate, which is why alternate dosing is used.


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## EnderUK (9 Feb 2015)

ian_m said:


> In the tank the pH isn't so low (hopefully)



Might be why I don't seem to have a problem.


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## Andy Thurston (9 Feb 2015)

EnderUK said:


> Might be why I don't seem to have a problem.


I was just thinking that about your water.
From tap and left to settle overnight ph6.9
In tank at lights on ph 5.6
I've been dosing both together for about a year no nutrient deficiency here, only co2 from poor flow etc.


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