Having read an awful lot of great info on this site from some very experienced plant growers, I've found myself in the situation where I seem to have read loads but seam to be none the wiser!.
As an example, I would like to ask what would be the ideal water parameters in the following scenario:
There are three identical tanks, all the same size with the same lights, substrate, co2, plants and using EI ferts regime with EDTA dry salts.
Tank A use's 100% RO water, PH 7.
Tank B use's 100% Tap water with a GH of 18 & a KH of 11, PH 7.8.
Tank C use's a mix of RO and tap water to get a GH of 5 and a KH of 3, PH 7.2.
Tank A.
As RO water is free of all carbonates I believe it is unsuitable to grow plants because it has been stripped of all essential nutrients that plants need. Plus, it is prone to rapid PH swings because the lack of alkalinity of RO water effects its ability to resist (buffer) Co2 gas absorption.
Tank B.
Better in terms of it's ability to provide a source of calcium/carbonates to plants, plus the alkalinity helps 'buffer' against rapid PH swings?.
The major drawback is even with high co2 injection,the PH is unlikely to drop below 7 without gassing your critters.
This will directly effect the EDTA Chelator used in micro ferts making them unavailable to plants.
The EDTA chelator is only effective on a PH lower than 7.
Tank C.
Err, sounds about perfect!
Is the above right? or do I need to read a bit more!
As an example, I would like to ask what would be the ideal water parameters in the following scenario:
There are three identical tanks, all the same size with the same lights, substrate, co2, plants and using EI ferts regime with EDTA dry salts.
Tank A use's 100% RO water, PH 7.
Tank B use's 100% Tap water with a GH of 18 & a KH of 11, PH 7.8.
Tank C use's a mix of RO and tap water to get a GH of 5 and a KH of 3, PH 7.2.
Tank A.
As RO water is free of all carbonates I believe it is unsuitable to grow plants because it has been stripped of all essential nutrients that plants need. Plus, it is prone to rapid PH swings because the lack of alkalinity of RO water effects its ability to resist (buffer) Co2 gas absorption.
Tank B.
Better in terms of it's ability to provide a source of calcium/carbonates to plants, plus the alkalinity helps 'buffer' against rapid PH swings?.
The major drawback is even with high co2 injection,the PH is unlikely to drop below 7 without gassing your critters.
This will directly effect the EDTA Chelator used in micro ferts making them unavailable to plants.
The EDTA chelator is only effective on a PH lower than 7.
Tank C.
Err, sounds about perfect!
Is the above right? or do I need to read a bit more!