How do you remineralize your RO water?

dw1305

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Hi all,
I added as per instructions, and this is where I think I have gone wrong, added alkaline and acid buffers.The TDS is over 300, so not much different to tap......Do the buffers add significantly to the TDS?
The rise in TDS is due to the both the "Seachem Equilibrium" and the buffers. Any compound that dissolves causes a rise in conductivity (TDS).
Do I need them?
No, you don't.
I dose DIY EI from Aquarium Plant food.
You don't need the Equilibrium either.
I know cutting with tap is easier and cheaper, but thought I'd have a play whilst I have no fish.
I think that is a good idea, get acceptable plant growth and find a <"conductivity (TDS) datum">, once your happy with the plants you can add the fish. If you want a dash of dGH/dKH you can just add some tap water to your RO, if you want a more regulated approach you can use the formulae to create your own custom mix.

Personally I'd try 90:10 RO:tap and see what the TDS value looks like, you definitely don't need more than 50ppm TDS from the tap (this has added Ca++ and HCO3- ions). Everything else you need is in the EI mix.

Have a look at <"Oh Wise ones - Is My Rising TDS.....">.

cheers Darrel
 

Geoffrey Rea

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Do the buffers add significantly to the TDS? Do I need them?

Personally, I don’t bother. TDS is about the same where I live and recently started up a tank with 50/50 RO and tap. Everything you add will only increase the total dissolved solids so you’re losing the benefit from using RO to some extent. If your concern is TDS that is. I know it remains a sore point on most forums but there’s very few instances in my experience where you need to bother with RO at all let alone shelling out on products for buffering.

Beat me to it @dw1305 :lol: Listen to Darrel, it’s good advice.
 

JMorgan

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OK I'll chip in because I used to use remineralised RO on some tanks before I down sized the "fish room" - I still have the gear because I like having the option, but I typically use tap on my two larger tanks and a tap and RO mix on my two smaller tanks. I'll also top off the larger tanks with RO occasionally. Depending on various things like TDS and duckweed index, if I've added an unusual amount more ferts I'll refill with a mix of tap and RO simultaneously until the TDS is about right. It really doesn't have to be precise - just ball park.
I generally find if I keep my TDS to under 150ppm critters and plants are happy, but this probably has as much to do with what they're used to, than being anything to do with what they actually need. In other words I'm sure they'd all adapt to my tap at around 350 to 400ppm, but having kept them under 150ppm for six or seven years it's what we're all used to.

I've kept a few single species tanks of apistos and corys at much lower TDS (under 100ppm) and they've bred successfully - what I don't know is whether I'd have been equally successful breeding them without all the fussing about with RO! I've a growing suspicion (with at least some of the easier to breed species) that what I've been thinking about as being RO dependent is possibly much more to do with not using a dechlorinator, but aeration (I don't have chloramine). This is because I know certain corys and ancistrus just don't spawn if youre using a dechlorinator and also daphnia and other micro critters don't like it either, so its obviously having some effect on the fish, if unobservable directly. Talking to some old blokes who kept fish in the 60's they were saying that it wasn't unusual for species like cardinals ( Paracheirodon axelrodi) to breed spontaneously in community tanks, long before anybody started adding dechlorinators, but just 'aged' their water - Anyway off topic!

I have a 120L blue food safe barrel with an auto shut off valve to store the RO. This has a pump permanently plumbed in, leading through a hole in the wall to the tanks. I have the plumbing set up so I can direct tap water directly into the container or bypass it to feed the RO unit - that way I can mix and aerate. The pump is on one of those wirelessly controlled plugs so I can power it on and off through the wall. Incidentally for those contemplating using RO remember it is pretty throughly deoxygenated by the process and depending on your set up may not remove chlorine, so aerate the hell out of it.

I have previously played about with fixing extensions to the auto shut off to stop the RO unit at a given % of the volume of the barrel, but while these sort of worked it was very much a DIY bodge involving super glue, zip ties and various sizes of plastic bottle as my 'float' and it is simpler to just fill it to the desired level with tap water first and top off with RO. Of course you have to figure out what that % will be before hand.

A decent pump and a hose are all you need to avoid breaking your back and if there's one thing I've learned to invest in its avoiding carrying and lifting large volumes of water - so I pump out the old and pump in the new, unless using mains pressure or a siphon of course. The point is don't lift, pump!

I think my past adventures in DIY remineraliser were very valuable educationally, despite experience proving them to be largely unnecessary, and on that basis I'd recommend it to those interested. It certainly underlines how much markup there is on these off the shelf jobs and encapsulates IMO pretty much everything that's wrong with the aquatics 'industry', surpassed only by the shameless proceedings of those companies selling Bentonite and Montmoriliionite to shrimp keepers in 10g bags, when they extract the stuff with bulldozers to surface football pitches by the ton, probably for comparable sums!
 
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jaypeecee

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Incidentally for those contemplating using RO remember it is pretty throughly deoxygenated by the process and depending on your set up may not remove chlorine, so aerate the hell out of it.

Hi @JMorgan

You make an interesting comment above. I get RO from my LFS. Do you think your comments about deoxygenation and chlorine content would still apply to their RO water?

Thanks in advance.

JPC
 

JMorgan

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I have nothing very scientific to offer, but here's how I join the dots: First of all thoroughly aerating water isn't going to hurt anything, so why not? In theory the carbon block part of an RO system should sort of the chlorine, but then there's variables such as how long ago it was changed and how much chlorine your tap or your LFS's tap water contains. Since the old school way of dechlorinating was just to let the water "age" for 24-48 hours before water changes and we know this can be accelerated by chucking in an air stone, again why not?
In theory the chlorine in the tap should make it impossible for archaea and bacteria to colonise the RO filters, but archaea live in some of the harshest environments on earth, so until someone proves different, I'm going to assume that by the time water has passed through any filtration system, including an RO unit, its pretty low in oxygen.
By the way, please don't confuse the notion of "aged aquarium water" where people used to think it was a good thing not to do any water changes, and 'aging the water' which is just letting the chlorine dissipate for a couple of days, without adding dechlorinator. I wish I were better organised so as to cite the breeders who mentioned they'd stopped using dechlorinator and that this had very quickly triggered spawns after months or years of getting nowhere and was the only thing they changed. I don't want to name drop least of all inaccurately! Of course with many species it seems not to make any appreciable difference, or other factors are much more critical.
 

ian_m

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Do you think your comments about deoxygenation and chlorine content would still apply to their RO water?
Ideally your LFS RO water should have been tested for chlorine and ammonia, which are the two chemicals that appear in RO water when the RO unit is not optimal and/or failing. A lot of people just add small amounts to Prime to their RO water, just in case, as it saves relying on possibly unreliable test results, though technically as you are only testing for one ion in "pure water", the test result should be free from other ions interfering with the results. The one and only case a hobby grade test kit will probably be OK to use.

The chlorine in RO water comes from poor quality or old or incorrect type (de-chlor pre-filter ?) or flowing too fast carbon prefilter.

The ammonia comes from the break down products of chloramine not be removed by poor quality or old or incorrect type (de-chlor pre-filter ?) or flowing too fast carbon prefilter.
 

jaypeecee

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In theory the chlorine in the tap should make it impossible for archaea and bacteria to colonise the RO filters, but archaea live in some of the harshest environments on earth, so until someone proves different, I'm going to assume that by the time water has passed through any filtration system, including an RO unit, its pretty low in oxygen.

Hi @JMorgan

Thanks for the feedback.

I'll test my RO water for dissolved oxygen and get back to you.

JPC
 

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