[Red_Rose]

I know that some people don't do water changes on NPT's if plants and fish are fine and that's what I've been doing. Aside from a noticeable potassium deficiency, I've often wondered if it's possible to end up with a calcium deficiency when water changes aren't being done? Is this possible even if the water that's being use to top up the tank is hard? I know that snails and plants will use up calcium but could it lower to the point where plants start suffering from a deficiency?

 

[Dustymac]

I've often wondered if it's possible to end up with a calcium deficiency when water changes aren't being done? Is this possible even if the water that's being use to top up the tank is hard? I know that snails and plants will use up calcium but could it lower to the point where plants start suffering from a deficiency?

Interesting. I suppose it's possible. It would assume a high overall growth rate for water hardness to drop faster than it could be replenished by what is lost through evaporation. But there are so many variables: light levels, CO2, number of fish, plant density, temperature, etc...

Given that minerals are left behind when water evaporates, could it happen the other way; could Calcium or other minerals accumulate faster than they could be consumed and pruned, making the water harder and harder with every evaporation replenishment? Since my tap water is ultra soft, I'll never be able to answer either question, but perhaps someone else can.

Jim