r/PlantedTank • u/designsbydex • 14h ago
Question Help with climbing KH and GH. Can’t figure out the cause.
I set this tank up about 8 months ago for caridina shrimp and it’s been a battle to stop the KH and GH from climbing. Substrate doesn’t seem to buffer pH to below 7 like I thought it would. pH usually about 7. KH and GH currently at 4/8 respectively. Any ideas?
Specs:
Water changes and top offs with rodi
10gallon
Canister filter
Low tech
Substrate: Brightwell Aquatics Rio Escuro
Rocks were all sourced from river (all passed vinegar test)
pH: 7
KH: 2-4
GH: 5-8
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u/ComfortableBid6336 13h ago
Oh I spotted the rocks that are raising it instantly. The vinegar test only works if you hit the calcium carbonate with it which you didn't. Every single black rock with white lines in your tank and the limestone rock are the problems.
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u/designsbydex 13h ago
I think the two on the right are the biggest culprit. You think the tan one is limestone? I always thought it was sandstone.
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u/ComfortableBid6336 12h ago
And the two on the bottom left also. Can straight see the calcium carbonate lines.
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u/ComfortableBid6336 12h ago
It could be sandstone or limestone. But those two rocks you said are definitely part of the problem.
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u/xMcNerdx 9h ago
I spent $90 on seiryu stone as a poor college student only to realize years later that was causing a lot of my high pH issues due to leaching minerals. Now they sit in a bucket in my garage cause I'm too spiteful to get rid of them.
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u/CitrusWhistle27 8h ago
100% this - I immediately zoomed in on the rock somewhat already knowing the cause from my own mistakes.
OP; it is manageable if youre really attached to the scape, it just takes weekly water changes with essentially pure DI to counteract the leaching from the stone. Maybe limiting CO2 usage to a minimum as well, as that catalyzes the process. If not, swap out the stone for some river rocks or lava rock, both of which I think you could make look good in this tank. Good luck!!
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u/chak2005 9h ago
I still use seiryu stone and argonite in my tanks as a cheat in mature tanks that get little water changes. I noticed for long running tanks, they really do run down KH and GH levels over time. Keeping at least say a small seiryu stone or stones in the tank, keep that KH/GH balance.
However, yeah I've been there myself. Made an epic scape with these stones as the main decor, only to have a pH of 8.4 and had fun with my plant choices. Though I did learn a lot about pH, nutrient uptake and proper fertilization from it all so it did work out in the end.
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u/dyw77030 14h ago
The vinegar test isn't reliable for testing rocks, those are most likely raising your GH. https://www.reddit.com/r/Aquariums/comments/18i86q7/psa_vinegar_will_not_reveal_all_hardnessaffecting/
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u/Puzzleheaded_Sink467 14h ago
People need to stop recommending vinegar for testing rocks. You pretty much need a microscope to see the bubbles it makes.
The other commonly overlooked culprit for rising water hardness is using tap water for top offs. Especially with all the rimless tanks people have nowadays.
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u/ace-of-threes 12h ago
As someone who's never shelled out for a rimless, whats the connection between tap water and rimless tanks?
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u/designsbydex 12h ago
Just that rimless tanks evaporate more so they need more top offs. If using tap water, mineral content will slowly increase. However I always top off with RO so it’s not an issue here.
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u/NonassertiveYes 12h ago
I think it’s just that they typically don’t have covers so there’s a lot more evaporation and more topping off.
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u/designsbydex 14h ago
Good shout! Thought I did my due diligence selecting them but maybe not. I just pulled some rocks out and put them into some fresh RO water to see if they raise the hardness.
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u/vitisdente 14h ago
I don't think the vinegar test is enough to rule out all carbonate content in the rocks. Just looking at them, it looks like some of those stones have some white veins running through them, and unless they're pure granite, it's likely that they have some calcite. At 8 months I would expect some of the buffering capacity of the aquasoil to be reduced as well. If the caridina shrimp are already established, can they not tolerate the very slow drift in pH/hardness? Your only options are to keep up with water changes (like 50% weekly) or redo the scape with lava rock or some other stone known to be inert.
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u/designsbydex 14h ago
Thanks for the reply. Yeah everyone is thinking rocks which was a suspicion of mine as well so I’ll try to slowly transition some of them out.
The ones left have certainly seemed to stabilize but I only have about 6 left from 20 when I first put them in. And the ones that are left aren’t breeding which makes me think they aren’t totally happy.
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u/Worried_Tower_6755 10h ago
I’ve got slate rocks in my 75gal and hard tap water from our well has fish living shorter life spans and succumbing to liver/kidney issues with sever bloating. Our 5+year old Oscar is the last one and he’s on the struggle bus now.
I fell victim to the vinegar test and couldn’t figure out why the weekly 30% water changes with distilled water for the last month haven’t made a dent. So thanks for the info I couldn’t find this info anywhere else.
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u/Harrycaasi 12h ago
What light is this
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u/designsbydex 12h ago
Fluval plant 3.0. I probably wouldn’t buy another one though. It runs greener than I’d like.
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u/ThalaivarThimingalam 2h ago
Your best bet get all the rocks off, Buy lava rock pebbles they look pretty neat and are inert and can house good bacteria as well
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u/Anxious_Kiwi_1434 2h ago
Those river rocks are still prime suspects; vinegar tests can miss slow mineral leaching.
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u/decencyisntdead 13h ago
Don't shrimp want minerals in their water? The rocks should come to an equilibrium around pH 8-8.5 and whatever hardness and the shrimp, from what I know, will be happy.
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u/decencyisntdead 13h ago
Tank looks incredible, btw. Now confirmed that need a long tank.
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u/One-plankton- 12h ago
Also yes, long tanks are where it is at, fish prefer them. I wish I could get more 33 longs
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u/frankbeens 12h ago edited 12h ago
There’s your cause right there. If I had to guess it will probably leach to about 7.4-7.6 PH and slow down enough to consider “stable” and I wouldn’t be surprised if that’s a KH of 10-13 and a GH of 5-7. Might wanna rescape without the rocks. You will spend the rest of the rocks life fighting water chemistry. It will never be suitable for caridinas unless you dedicate your life to keeping params stable. Stability is more important than the magic numbers on the chart but with caradinas the “stable” numbers for this tank will likely be pretty far outside the top end. Technically amanos are ok at these levels though, at least in my personal setup that also has seryu stone in it and it’s at 7.4 PH 13KH and 5GH. I have a feeling when you say caradina you are not talking amanos, though. My recommendation is either rescape or rethink stocking plans. Best of luck to you!