[sun697]

Have an established 5 gal planted, shrimp tank and can't quite seem to keep my GH down. Current params are TDS 250, GH 20, KH 4, pH 7.4. Ca per the API test kit is 120 mg/L.

Shrimp are generally doing okay (they're relatively new though, only about 3 months) but have had some failed molts it seems -- this is why I want to try to lower GH. Tap GH is about 8. I was able to drop the GH to about 15 with a series of small RO water changes but it seems to have climbed back again over the course of 2 weeks maybe.

I have Fluorite substrate and some dragon stone (which is supposed to be inert -- but could that be a source of extra Ca?). Also, would you expect TDS to be higher with a GH of 20?

Thanks!

 

[minorhero]

Your gh should not be 20 if your water source has a gh of 8 and your tank had dragonstone and fluorite substrate. This means one of the following:

1) there is a mistake in your gh test, either doing it wrong, dirty tube, etc., 2) you are adding something to your water that raises gh like seachem equilibrium etc, 3) your tank does not have real dragonstone in it, its another stone that raises gh, 4) your dragonstone was covered in clay that raised your gh. 5) there is something else in your tank other then fluorite and dragonstone in your tank.

If you are doing large regular water changes I would expect your gh to go down if it was clay on the dragonstone but it might be too early. Either way if you know its not 1, 2, or 5 then you can make an immediate difference by removing the dragonstone. If you wash it really really well and put it back and you still have the problem then you know its not 4. No matter what though you will need to do a very big water change to clear out what is in the tank.

 

[jaz419]

My TDS is usually hovering around 350 with a GH of 9 and KH of 2.

This is just anecdotal experience, but at a TDS of 250 would have much lower GH than 20.

My initial guess would be testing or meter error


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[sun697]

Thanks so much, minor and jaz. I'm relatively new to this but would also expect TDS to be higher for GH 20. Seems odd. I'm using API GH/KH test kit and it seems to check out okay in that it showed zeros for GH/KH of the RO water.

I'm going to try to take out the 'dragonstone' (maybe try the vinegar test on it too) to see if that helps. Thanks again.

 

[jaz419]

Attach a pic.... might be identifiable as not even dragon stone. Although it’s a pretty easy one to get right, so I don’t expect that’s the case lol


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