Help me understand GH

[KentFishFanUK]

Hi guys me again, been a while, back with more questions for you wonderful people. 

This time I'm trying to understand GH specifically. 

So I get that like mostly calcium and magnesium right? And technically it's separate from KH and it doesn't affect pH right? 

I know that with most fish stable parameters are more important than specifics and they will acclimatise to whatever. I also know fish and shrimp, plants etc will all need at least some calcium and magnesium to live. 

That being said my tap water is over 21°dH or 375 ppm which is quite high already but add to that some of my tanks require quite regular top offs due to evaporation (even with lids) and I am worried it's going to go up even more? 

I don't have access to RO or distilled water and the tanks in question are just small fry grow out tanks (or even egg hatching Tupperware containers) so only running small sponge filters so can't add a water softening pillow or peat moss to them (to be honest I'd rather not anyway as in such small tanks I'd imagine it could change parameters very quickly if I like forgot to take it out for a while). 

Do I have to worry? What affect could too much hardness have on eggs/fry/fish/shrimp?

Would moving eggs from a tank with medium hardness and putting them in my super hard treated tap water affect them? I'm sure I heard it said that they will adapt to conditions better if they hatch into them. My panda corydoras keep laying eggs in my community aquarium (pH/KH and GH all much more in the middle or parameters) but they keep getting eaten so was considering pulling some and hatching them out in Tupperware. 

I saw one article that said Cattappa leaves are 'proven' to reduce GH as well as KH but didn't cite any references or explain how. Another article parroted that and then went on to explain it does this by releasing acids as it breaks down - I thought that acids only affected KH/pH though? 

Do botanicals like drift wood and leaves etc reduce GH as well as KH somehow?

Could plants theoretically take up enough out of the water to lower it? Even my fry grow out tanks have quite a lot of plants (and algae). 

 

Thanks in advance all! 

[ange]

If this is what your livestock are used to, odds are you're fine. Buildup is possible over time but you'll mostly see that in the form of limescale.

From a layman's perspective, high KH means that your fish are more likely to develop healthy bones and your invertebrates are more likely to have healthy shells/exoskeletons. This is especially critical for livebearers.

Minerals dissolved in the water column don't evaporate (much like how aquarium salt has to be removed through water changes) so can accumulate over time. If you want to look at resources about how buildup ramps up I highly recommend looking into marine resources as this is something frequently looked at by marine aquarists. Unfortunately the solution is generally to use RO to top off.

If you have any terrestrial plants I highly recommend trying to do "water changes" by using tank water in your garden. This is what I've done with my tanks and the plants definitely appreciate my fish water so I don't feel like anything is going to waste.