Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
If you want to try peat moss for this here is how:
Get a gallon of Reverse Osmosis or distilled water.
Mix it with tap water in several ratios:
25% RO + 75% tap
75% RO + 25% tap.
Test those mixes (GH, KH, pH, TDS), and compare to the tap water after it has sat out overnight or longer.
(If you put these in 5 gallon buckets the next test is easier)
Which one comes closest to what you want for your tank?
Now add peat moss to the tests, and include a bucket of pure tap water. Perhaps as much as 1 cup of peat moss per 5 gallon bucket. Stir as often as you can. If you have any sort of small pump or air bubbler that can do the stirring for you.
About every 24 hours test the same as above, and record the results. Run this out 2-3 days. Longer is fine.
How to interpret the results:
Peat moss varies in its action. Sometimes all it seems to do is release organic acids that turn the water yellow to brown. This may not even affect the pH if the KH is too high.
Other times peat moss can act like an ion exchange water softener, removing many of the minerals that raise the GH and KH. Then the pH can drop really low. This may take a couple of days. This sort of result will be maximized if you have already removed a lot of the minerals, which is why you are testing tap water mixed with RO.
How to use the results:
Once you have found a recipe that works you will need to prepare the water to fill the tank and for water changes ahead of time. 24 -48 hours is usually enough.
Fill a garbage can if you have a large tank or several tanks, with a mix of RO and tap water. Add peat moss in a bag (I use a knee-high nylon stocking, on knee-hi of peat for 20 to 40 gallons of water). Circulate the water. You can add dechlor. If you want to add plant fertilizers, do this right before the water change. You can hang an aquarium heater in the garbage can to keep the water the same temperature as the tank.
If your fish are currently acclimated to hard water than make the change very gradual, no more than about a 10% water change for 3-4 water changes spread out over a couple of weeks. Then perhaps 25% water change for 3-4 water changes, again spread out over a couple of weeks. It may take a couple of months to get the tank water as soft as you want it, but the fish acclimate slowly, and this is safest.