02-20-2010, 06:40 PM
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Originally Posted by redchigh
So does that mean I have to choose to save either my plants or fishes?!
I guess I'll have to do a bunch of wc's and go buy some gravel :-/
oh and btw, I read somewhere that if there's not sufficient CO2 in the cater, plants can use carbonates for photosynthesis instead (with some effort). Just a useful little tid-bit.
The point I'm trying to get across is that you have to be careful and work slowly when changing water parameters. The Aponogeton issue could be caused by any one of several nutrient-related aspects. You have added a fair bit of calcium via the chalk (your fluctuating pH readings aree proof of this) and that is certainly one possible cause; another could be inadequate nutrients in general--are you using any liquid fertilizer, and if so, which and how much? A third possibility is that Aponogetons go through a dormant period (some hybrids are apparently exempt from this, so I've read) and this could be related to that. I have aponogetons but I haven't studied them in much detail, which is to say none.
Dolomite gravel in a nylon bag in the filter or next to the filter outflow, would be safer. I have half a cup or less in the filter of my 115g, and it adds 2 dGH and maintains a stable pH of 6.0. In the other two tanks with no dolomite, and identical tap water, plants, light and maintenance, the pH is 5.0 and zero GH. So the dolomite works. I have maintained this for 12 years without any problems.
On the plants and carbonates, I mention this in the stickies. Some plants are better at assimilating carbon from carbonates than others, and these plants, like Vallisneria, do better in harder water for that reason. Other plants are not very good at this, particularly bog plants such as swords and some species of crypts, because these plants in nature live part of the year emersed and obtain carbon from CO2 in the air. Studies found that some plants such as mosses are basically unable to use carbonates as their source of carbon.