Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Here is a test you can do to figure out what you are getting into:
Go buy a gallon of Reverse Osmosis or Distilled water. (They are the same from an aquarium point of view). IF you get these out of a vending machine test to be sure they are keeping their filter in good shape. GH and KH should test 0 and TDS should be under 10.
Make several test batches with your tap water, making perhaps a cup or two. Enough for testing purposes.
Try 25% RO + 75% tap.
75% RO + 25% tap.
Test GH, KH, pH, TDS.
Whichever comes closest add some peat moss (small handful in a cup or two of water is plenty). Stir and test again at 24 hrs and 48 hours, then again a few days later. Did the results change? Are they stable?
Here is how I did this when I kept soft water fish that demanded very soft water:
1) Prepare the blend of RO + Tap, making sure the GH and KH was where I wanted it or lower. (For what I wanted, starting with my tap water, I usually used 50% RO + 50% tap)
2) If I needed to add a little bit of Equilibrium to raise GH or baking soda to raise KH. (Usually not needed- my tap water has a nice ratio, just a bit too high)
3) Add a knee-hi stocking full of peat moss to a garbage can of water (20-40 gallons). Circulate this with a fountain pump overnight. (Careful! The stocking can get sucked inside the intake of the pump) The knee high of peat moss would last for several preps, but take longer after it had been used a few times.
4) To heat the water I would do any of several things such as heating it on the stove just before use, adding an aquarium heater, or making it too soft, then adding hot tap water just before use.
Top off with pure RO water (or distilled)