Akeath

My 75 gallon community tank is full of fish who prefer slightly acidic water, 6.0-7.0 pH to be exact, and 8-12 dGH.

My tap water is off the chart pH (above 8.6, probably considerably above) and 10 dGH.

For the last 4 months (exactly 4 months, actually) I have been using 2 pieces of African Mopani wood and a product called Proper pH 7.0 in this tank, and have had exactly 8 dGH the entire time, and a pH consistently between 6.6-6.8. The fish are thriving and breeding in these conditions, and that makes me happy.

However, the correct dosage of Proper pH 7.0 for this tank means I go through lots of bottles of that chemical, and it is getting really expensive. So I am thinking about other methods to acidify my extremely alkaline water to the levels that my fish prefer. And yes, I know they could probably adjust somewhat, but between spending a lot and making them adjust to conditions that aren't ideal for them, I'd rather continue spending a lot, no contest whatsoever. More over, my tap water pH is beyond reasonable levels for most fish. I know that none of the other chemicals meant to acidify water will work for me, most of them just bounce right back to extremely alkaline, and the last thing I want is to have a constantly and radically shifting pH. And my bogwood does not make enough of a difference by itself.

So I was thinking about getting some peat and using it, perhaps in the filter. But I'm not sure how to use it, how much to use it, and I am very concerned about the hardness going down to the point that my water has no buffering capacity, and my pH then going absolutely crazy. I was hoping that someone with experience using peat could help me with these issues.

I would also like to hear from people who have used other methods besides peat, bogwood, or chemicals. (If there are any other reliable ways).

Sorry the post was so long, thanks for reading it!


Oh, and here is the list of things in red that was suggested I include:
* Last water parameter check on 11/09/09 results: 0 ammonia, 0 nitrite, 10 nitrate, 6.6 pH, 8 dGH. Current temperature: 75 degrees F.
* Tank Mates: 10 Harlequin Rasboras, 5 Gold Tetras (eventually getting 5 more), 6 full grown or almost full grown Panda Cories and 3 Panda Cory fry. After everyone has grow a bit bigger I will get 5-7 Praecox Rainbows too.
* I vacuum the substrate once a week and do 1/3 of a water change once a week, I added in fresh carbon yesterday.
* I feed tetramin tropical flakes, Hikari sinking wafers, TetraAlgae vegetable enhanced crisps, freeze dried brine shrimp and small freeze dried medley (mysis shrimp, daphnia, bloodworms)
* 75 gallon tank, real Mopani wood, two Aqueon submersible 300 watt heaters, a 40 watt light, 2 Penguin Biowheel 350 power filters with tons of Bio-Stars, a lot of various different types of foam, and water polisher as filter media and a small amount of carbon.
* I performed a fishless cycle several months ago.

TedsTank

I use RO water and add tap water to set my ph (8 cups to every 6 gallons of RO). You could use distilled water also. Problem is with a 75 Gallon tank, that is a lot of water adjusting and/or RO or distilled water. I weighed out the differences and bought a countertop RO unit....can get up to 9gallons and hour. If I had to do it again I would get a larger unit. For the amount of water you have, i can't can't come up with a easy fix.
Oh yea, my countertop RO unit was $250 at the time. Way cheaper than Ph down or Discus buffer chemicals in the long run....and much safer to use.

pepetj

I do use peat filtration to lower pH. I found the Fluval Peat Fiber but not the Fluval Peat Pellets to work well for me. Using peat does require frequent monitoring of KH and GH. If you do not want tea colored water keep up with activated charcoal filtration.

As for the amount used, I'll give you my parameters as guidance: from pH 7.7 8dGH 5.5dKH (from my source water) I got to pH 6.8, 5.5dGH, 3.0dKH in a 30gal Breeder tank (that likely has 26 gals of water once substrate, driftwood, submersed equipment parts, plants, rocks and fish volumes are considered) using roughly 1/3 to 1/2 of the peat fiber contained in the package.

The advantage of peat is that you won't get sudden pH variations if you keep an eye on safe minimum DKH (I consider 2.5 as safe) as the raise in pH, once peat fiber active time is due (usually 6-8 weeks in my tanks), is gradual over time, not sudden.

Another means I use to lower pH is injecting CO2. Adequate levels of dissolved CO2 via pressurized (I'm waiting for my regulators) will drop pH by a full point value (e.g. in my case to 6.7 from 7.7). With DIY I have managed to achieve a drop from 7.7 to 7.0 (with 24ppm at lights off and 12 PPM with lights on of dissolved CO2). DIY can be a challenge to regulate.

Indian Almond Tree Leaves also work but not as effectively as peat fiber. I attain a drop to 7.2 from 7.7 in my 145gal tank (likely holding 115gals of water, maybe a less) using 18 mid to large sized leaves (I get them for free in the street I live, all year round). Leaves need replacement every 2 to 3 weeks.

Also, as TedsTank suggest, I mix RO with tap water. I am using RO processed drinking water that comes quite cheap locally (TDS <20ppm) in 5gal containers for USD1.25. I just ordered a 50gpd RO unit that I intend to use for my Nano Reef, and possible, for keeping Discus (if I ever dare to).

I have been using those methods either alone or in combination. My FW tanks pH range from 6.2 (Severum tank) to 7.8 (Cherry Shrimp tank).

I do tamper with pH but it does take a lot of effort to keep up with. I also go from less to more as I experiment around. I did manage to crash the pH of an experimental tank from 7.7 to 5.0 using peat fiber.

Pepetj
Santo Domingo