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soft, rain water questions

2657 Views 7 Replies 5 Participants Last post by  Edward
Hi, I have a couple of questions if you dont mind taking a look at.

I noticed by reading previous posts that you use strictly R.O. Water.

Well, my tap water at home is strictly rain water. I have a 10,000 gal catchment tank which is always full... Its rains so much here.

After testing my water, I have found the KH to be 0 or maybe 1, and GH to be 2 or 3...PH is 6.0 to 6.2...

My question is, is this sutiable for plants or do I need to be adding something?

Here is what I have:
c02 regulator set-up (azoo brand)
Coralife Frestwater CF 260W

What should I be adding to my water? Do I need to raise the KH a bit???
What about the PH? will it be too low after the addition of c02?

I haven't yet set-up this tank... I wanted to get everything set before I started.

If I do need to add something to my water, then how ofter and how much should I be adding? After each water change?

I have read the R.O./ D.I. post but don't fully understand it? (new to this)

Next question pertains to Ferts...

I have Flourish and Flourish Iron but want to do a PMDD type...

What kind of "recipe" do you suggest I put together... being that I have soft water?

I know this is a lot of questions but thanks in advance for any advice you can give me.

Thanks Josh
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Seachem makes Equilibrium, which raises the gH, it also gives you about 50ppm of potassium, calcium, and magnesium. So you never have to worry about dosing neither of them. This product should be used after every water to keep your gH at where you want it.

For the kH and pH use the Alkaline buffer and Acidic buffer, also by Seachem, this gives you the ability to target your pH at where you want it(check their site, they have a ratio chart to tell you how much you need to dose to get the desired pH). This should also be used after every water change.

Search for 'Liquidoser' or check out the Perpetual Preservation System for fertilizer recommendations. Infact Jay has the same size tank, so you can use the same values, except you don't need to dose calcium and instead of dosing P dry you can use Fleet Enema instead.
I use rainwater because my tapwater has nothing but sodium bicarbonate in it. It has a lot of sodium bicarbonate, giving it a KH of 9 or 10. There is no measurable calcium or magnesium, and I get a GH of 0. It is actually harder to get adequate calcium into solution with this tap water than it is with rainwater, probably because the rainwater has a much lower pH, encouraging the calcium carbonate to dissolve faster.

Ground limestone goes into solution slowly and lime (calcium hydroxide) goes in more rapidly. One has to be more careful using lime, because it is quite alkaline and could injure fish and invertebrates if too much is added at once. It is a good idea to add CO2 while adding lime to keep the pH under control. Calcium chloride is highly soluble and ought to be dirt cheap because they use it as a de-icer. Kent turbo-calcium is basically calcium chloride.

Whatever source of calcium you use, you ought to get the GH up to at least 5. GH measures magnesium, also, and most lime and ground limestone is actually part magnesium and part calcium.

See the thread on burned/curled leaves-tips on how to improve the condition. Somebody there said that a GH of 4 was not enough to cure the deficiency symptoms.
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so what would be the proper way to raise the KH and GH?

Baking soda, epsom salts, calcium chloride? (Id rather use this stuff than the seachem equilibrium stuff)

If I have a 55 gal tank.... what would be the proper doses?

Thanks Josh
so what would be the proper way to raise the KH and GH?

Baking soda, epsom salts, calcium chloride? (Id rather use this stuff than the seachem equilibrium stuff)
Baking soda raises KH (alkalinity), but has no nutritional value for plants and makes it harder to get enough calcium in the water if you are adding calcium carbonate. I don't recommend it. Instead, use limestone, clam shells oyster shells, egg shells or some other use of calcium and magnesium carbonate. Or, for a quicker fix, use lime, but be careful and monitor the pH.
I've used Equilibrium on RO only tanks for years and it works VERY well. Three tablespoons of the stuff per 50% WC on an 80g tank reconstituted the water and made the plants very happy. There are other chemical reconstituents available, but none of the other options provided Ca, Mg, and K in the quantities Equilibrium does. I even use it on my tanks at home that get tap water.

If you're adding Magnesium, Calcium, and Potassium in quantities sufficient for the plants you're already re-constituting your water. Adding some form of carbonate or bicarbonate is all you really need to do as a pH buffer with CO2 supplimentation.

Phil, So what your saying is to add only Equilibrium and I should be fine? For the KH and GH? or should I still be adding the epsom salts and calcium chloride with the Equilibrium?

For a 55 gal tank how much of each should I be adding?

Thanks Josh
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