In one of those links above, there is a discussion about liming a fish farm pond. They state that if you use agricultural lime, that it will not raise the pH above 8.3 (under normal conditions) no matter how much you add. The even recommend adding a great deal to fish farm ponds before they are even filed because it is so much more difficult to add it once filled with water. Adding more than necessary at one time will only extend the time period between liming applications because it only dissolves as needed.
For my little 1,000 gallon fish tank, I could add some decorative limestone blocks in the actual fish tank or ag lime once and it will probably last indefinitely. They say that it will only leach out as the water conditions demand it. My tap water is probably sufficient in all regards not to require doing so, but if there is no problem in adding excessive quantities of limestone, why not incorporate that right off from the start?
Mainly what I am thinking is going to the limestone quarry that is just a few miles away and buying some interesting chunks of broken limestone and building habitat shelters in the tank with them. They would provide hiding places for the fish, like caves and overhangs, but would also serve as the source of calcium carbonate and CO2 via minimal leaching into the water. If the water begins to trend towards acidic pH, the CaCo3 would be basically supplied as needed from these natural sources. With these large blocks of limestone, the leaching would be very slow and measured. Thus, it would be a consistant and self-sustaining system to hold the pH balance.
With the bio-converter bacteria (and the zeolite filter to take up any slack while the biofilter is getting established or recovering from winter) and the limestone in the pond, plus my input of aeration and water circulation, I am hoping for a nearly self-sustaining system.
In addition to the limestone chunks, I am thinking that I will also use ground egg shells from time to time. I looked this up and bird egg shells or readily available chicken egg shells contain roughly 94% calcium carbonate [CaCO3], 1% calcium phosphate [Ca(H2PO4)2], 1% magnesium carbonate [(Mg(H2PO4)2)] and 4% organic matter.
The phosphorous and the magnesium are beneficial, so this is also something, a way, to provide it slowly as required over long periods of time.
Do you think that this is a beneficial approach? Is there anything that you think that should NOT be done here? Keep in mind that I am raising bullheads (catfish) and not Koi in this environment.
I do have quite a good range of water quality to play with without fear of harming the fish. But, my goal is to keep the DO level high but never less than 10 mg/L, CO2 levels low and never greater than 8 mg/L, the alkalinity near 200 - 230, the ammonia and nitrite levels zeroed, the pH between 6.5 min - 8.4 max (desire a stable 7.4) and the temperature between 45°F - 82°F.
Please, any comments negative or positive and all suggestions are welcome. I need to ensure that I get it as close to perfect and as maintenance free as I can.
Thanks,
Gordy
