My own RO takes water with a TDS of 200 ppm down to less than 20. That is about a GH of 1. Although it is not perfect it is too much to be using for fish or plants without adding some buffering. For me that means adding back about to a 50 / 50 mix to get a GH of about 5. That is high enough for any fish I keep and low enough for my SA fish. If I also had a DI on the back end, I would expect a lot closer to zero GH. The point is that although RO/Right might work, and I bought some when I first got my RO. I have found that since there is nothing wrong with my tap water except excessive TDS, I can do fine by thinning it out with the RO and not spend a fortune on chemicals that are already present in my tap water. Anyone selling RO that is higher than 1 or 2 GH is probably not using a real RO to make the water. If they are selling DI with even 1 GH, they need to change their resin to some with some life left in it.
Water To Pure?
- Thread starter yellow tang
- Start date
I have thought about doing the tap/RO mix to reconstitute. I am just worried that my tap water, being city water, fluctuates to much for me to work out a guaranteed formula to hit a specific hardness. So I prefer having the "clean slate", if you will, of RO/DI to work with. It is interesting to me that the TDS of the city water going into my RO/DI is only 5ppm. PH out of the tap is 8.6 though. Which is another reason why I am using the RO/DI water in my FW tank.
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In my area the tap water does fluctuate but it happens slowly and seasonally. It happens slow enough that if I keep up with regular water changes it is gradual enough for my fish to adjust. For a long time I used mixes of tap and bottled water to try and keep the pH and hardness down. It was a complete mess. Since I have made the switch to pure tap water I haven't had any issues associated with water.
Using RO can be a big commitment that may or may not give you results you want. I am still intrigued by the idea of it though. I know what you mean with the clean slate. I feel like I can do anything with RO water, if I put the work into it.
Using RO can be a big commitment that may or may not give you results you want. I am still intrigued by the idea of it though. I know what you mean with the clean slate. I feel like I can do anything with RO water, if I put the work into it.
RO is just used to soften water, removes the GH/KH, do not worry about pH.
It'll be less after.
I suggest a blend of RO and Tap to hit a target KH.
That's what most do.
If city water is weird to you, then run a carbon filter only.
As far as planted tanks go, tap water is fine, especially if you plan on CO2.
Does not matter if it's rock hard or supper soft, I've had both for many years, there are a very limited far less common plants that do better in softer water, but overall, plants will do better in hard to medium hard water and the reason is rather simple(think KH).
Regards,
Tom Barr
It'll be less after.
I suggest a blend of RO and Tap to hit a target KH.
That's what most do.
If city water is weird to you, then run a carbon filter only.
As far as planted tanks go, tap water is fine, especially if you plan on CO2.
Does not matter if it's rock hard or supper soft, I've had both for many years, there are a very limited far less common plants that do better in softer water, but overall, plants will do better in hard to medium hard water and the reason is rather simple(think KH).
Regards,
Tom Barr
I am beginning to think this is part of the problem I have with plants.
my kH is 3..and only some plants do fine.
Actually it is pretty rare to get pH 7.0 in water. Ultra pure water is hungry and quickly scavenges CO2 and CO fromt eh air making it more acidic. Generally Ultrapure water quickly drops to a very low pH. Ours at work after a day measures less than 6 pH.
Maybe so, but out of the RO it should be 7.0. That's what I was refering to. :thumbsup:
RO water is rarely "pure", you need to run it through a few more steps, and DI is good for that, but a pH of 7 is meaningless in the context presented here and with basic aquarium keeping, we blend RO with tap to achieve a desired KH/GH, pH is really not the issue for fish, plants etc.
What is important to plants is CO2, O2, nutrients, light, and has nothing to do with the pH of the water as long as there is good stable CO2.
pH can be 7.2, but a KH of 20, or a pH of 6.0 and a KH of 1.
You do not even need KH at all(well, you cannot get rid of all KH in an aquarium, but close enough) to have fish/grow plants or use CO2.
You cannot measure CO2 using pH/KH though.
No KH part obviously
But plants do not need KH.
They grow fine without it.
They must have GH though, at least from the sediment or the water column(preferred). Ca and Mg and generally the anion SO4 and Cl are all plant nutrients so GH is a must have.
KH can be(a source of DIC), but generally is not(CO2 is preferred over bicarb).
With a tap of KH= 3, you should be able to easily grow any plant species you like, at least from the tap water's perspective(other things like good cO2, NO3 etc might be the issue, but not KH).
The goal when using RO was/is never this extremist view: pure water.
All it is used for is to reduce harder GH/KH's in water, not remove all the KH and GH (except in very rare cases or with folks using reefs that like to reconstitute and add salt mixes anyways).
Regards,
Tom Barr
What is important to plants is CO2, O2, nutrients, light, and has nothing to do with the pH of the water as long as there is good stable CO2.
pH can be 7.2, but a KH of 20, or a pH of 6.0 and a KH of 1.
You do not even need KH at all(well, you cannot get rid of all KH in an aquarium, but close enough) to have fish/grow plants or use CO2.
You cannot measure CO2 using pH/KH though.
No KH part obviously
But plants do not need KH.
They grow fine without it.
They must have GH though, at least from the sediment or the water column(preferred). Ca and Mg and generally the anion SO4 and Cl are all plant nutrients so GH is a must have.
KH can be(a source of DIC), but generally is not(CO2 is preferred over bicarb).
With a tap of KH= 3, you should be able to easily grow any plant species you like, at least from the tap water's perspective(other things like good cO2, NO3 etc might be the issue, but not KH).
The goal when using RO was/is never this extremist view: pure water.
All it is used for is to reduce harder GH/KH's in water, not remove all the KH and GH (except in very rare cases or with folks using reefs that like to reconstitute and add salt mixes anyways).
Regards,
Tom Barr
