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Can someone help me understand what's causing my GH to increase?

image05.jpeg wow just found this, you can see the stones better but also how the plants have come along. Not all those plants are still in the tank though or have been moved around along with additions but it's a vast improvement thanks to this places knowledge.
Hi @MichaelJ

That may not have been entirely representative of a tank setup. For example, 'prepped' RO water may be neither acidic nor basic, i.e. its pH may have been very close to 7.0. So, there may not have been any reaction between the 'prepped' RO water and the Eco Complete.

Just my two penn'orth.

@jaypeecee You are right to the extent that my experiment didn't completely represent the chemical markup of the tank setup. However:

The 'prepped' WC water (based on RO only) that I had the scoop of ECO Complete sitting in, included all the ingredients (Seachem Acid Buffer/Alkaline/Equilibrium) I used back then to target a specific KH, GH and PH (6.7-6.8 back then) ... So the water, at least for those parameters, was identical to the tank. I would not call my experiment conclusive by any stretch, but at least in my case I did not register any meaningful change to the TDS.
Furthermore, the OPs issue is rising GH and I never had that problem in my tanks (i.e. I never saw a gradual rise in GH) - only a gradual rise in TDS caused by the reasons mentioned in my post above (poor maintenance essentially). Ever since I changed my maintenance regime (following the advice and recommendations I got in that and several others threads) my TDS has been stable and exhibit a very predictable week-to-week rise primarily caused by plant/fish/food waste and ferts ... and both tanks still contain the same Eco Complete!

Hi @Marcus_F

It seems that Caribsea Eco Complete is as unpredictable as the British weather! Please take a look at this recent thread:


@jaypeecee This is not an accurate representation of the situation. In my case the ECO Complete substrate had an undetectable influence on the extreme TDS and no short term (at least) influence on GH.

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I also mix in Magnesium Sulphate (MgSO4) into my new water and I'll add that my GH reading of 11 drops was before I mixed this in.
Magnesium Sulphate will increase your GH. If you want to have Mg for plant growth and lower the GH use less tapwater and more 'pure' water.

I use rainwater as my 'pure' water (its free and in the garden)

My tap-water is moderately soft and I mix approx 50:50 with rainwater and add about 6 fistfuls of MgSO4.7H2O to 30 gals of water change. Bone idle I never check hardness or TDS just look at the plants and critters. [not much Mg in MgSO4.7H2O]. If you are of a mind you can workout the % by using Atomic Masses, think from memory its about 10 or 11%.

Hope this is of some use.
It has all the hallmarks of swimmer bladder disorder but then could that be caused by the hard water, I'm not sure.
Yes that sounds like a swim bladder infection. Possibly a neurological condition, but that seems unlikely across many fish of different species.
Swim bladder infections are difficult to treat, but an 'internal bacteria medication' could help.
Lots of people are keeping all the fish species you listed in hard water. They are quite robust and adaptable.
Yeah I wasn’t sure on the hard water and deaths, the shop I get the fish from are same very hard area and they use 100% tap water.
ive also kept cardinals in 100% tap water in another tank and they were with us 18months and then put in new tank for a further year. I’ve got some medicine coming for bacteria infections. I do think the very very high nitrate could’ve been the issue, I’ve no idea how long it was like it I guess nearly 4 months. Although I had two deaths after I spotted it and got it back to reasonable level I reckon the damage could be done already for those two.
I will keep with 50/50 as it does help with nitrate level, seeing 20ppm now in replacement water instead of 40ppm.
If the test kit is whack and not giving a true reading, it will give the same whack for both tests in theory so the important takeaway is that the difference is 10GH. So even bad test kits can be useful.
Hi @Marcus_F

The point you make is very relevant. Sometimes, absolute values are not critically important. But trends are important.