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Rising GH

M

Mizuel

New Member
Joined
18 Nov 2024
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3
Location
USA
My Gh normally rises slowly throughout the week. But last week I noticed it went up more than usual. I always do weekly water changes about 50% with RO water. I have co2 and fertilized once a week with 2hr aqaurist ATP e. I have ADA amazonia aquasoil with hakkai stones. My target gh is 3-5gh because I have cardina shrimp. I can't think of anything else causing the gh to climb so fast in a week.
 
hamfist said:
Do you have any calcium carbonate-based rocks or substrate ? They would be a classic cause of this.
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I only have hakkai stones and from what I know they are totally inert and don’t change the chemistry of the water. I did the vinegar test on them too. And I don’t have sand. I have aqua soil as my substrate
 
Maf 2500 said:
How old is the aquasoil and what is the GH of the water you use for water changes after remineralisation?
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It’s about 3 months old. The Gh is so high I don’t need to remineralize it after water changes. It’s at 5gh after water changes and by the end of the week it’s at 10-11gh.
 
I am not familiar "in person" with hakkai stones, but from looking at images they are irregular in shape, likely from one type of rock being eroded by water flow leaving the harder second type of rock behind. It would be reasonable to assume that the first part of the rock, that which had been eroded to create the funky shapes, was some type of calcium carbonate. If this portion of the rock is not completley eroded it will still dissolve just the same as seiryu stone (for example) would. If there are any white/lighter coloured areas of the hakkai stones around the eroded portions test this area with acid.
 
Do you have much evaporation and do you top up any significant amount with tap water during the week?
 
Maf 2500 said:
hakkai stones
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Hakkai river rocks should be inert unless your pH is extraordinary low which is improbable. I wouldn't blame the ADA amazonia either.... What other hard scape do you have in your tank - any funky (fun) decor ? a 5 dGH spike in a week is huge. How are you measuring the dGH?

Cheers,
Michael
 
Hi all,
MichaelJ said:
Hakkai river rocks should be inert
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My guess would be that it isn't the stones <"Hakkai Stone per KG">, even if <"they are composed of,"> or contain, limestone (CaCO3). The reason I say that is that the "real deal" (this picture is from the <"Aquarium Gardens"> link) looks <"very smooth and rounded"> ("water worn") and that only happens to really hard rocks.

hakkai-stone-per-kg-(3)-6099-p.jpg

Mizuel said:
The Gh is so high I don’t need to remineralize it after water changes. It’s at 5gh after water changes and by the end of the week it’s at 10-11gh.
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MichaelJ said:
a 5 dGH spike in a week is huge. How are you measuring the dGH?
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That is a substantial raise, infact large enough to be not easily explicable.

The calculation of just how much dGH that is, is here: <"How much calcium & magnesium">
dw1305 said:
I'm going to go for 1 : 1 Ca : Mg, so to get 6 dGH in 50 litres of RO:

We need 7.14 x 50 = 357 and 357 x 3 = 1071 mg and 1071 / 1000 = 1.071 g of Ca++ and CaSO4.2H20 is 23% Ca++ so 1.071 / 0.23 = 4.66g CaCO4.2H20 in 50 litres of RO water gives you 3 dGH, all calcium. The magnesium is the same calculation, but the numbers now are 4.35 and 10% giving you 6.53 g of MgSO4.7H2O.
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cheers Darrel
 
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Mizuel said:
My Gh normally rises slowly throughout the week. But last week I noticed it went up more than usual. I always do weekly water changes about 50% with RO water. I have co2 and fertilized once a week with 2hr aqaurist ATP e. I have ADA amazonia aquasoil with hakkai stones. My target gh is 3-5gh because I have cardina shrimp. I can't think of anything else causing the gh to climb so fast in a week.
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Are you running CO2 injection?
 
I must admit that I am very suspicious of any stone that isn't dragon stone these days. I test pretty much any new unknown stone. Best way is to put a lump of the stone in a bowl with just enough water to cover it. Test the GH and then test the GH again a few days later. Any rise must be due to the stone. I have found some "inert" stones to be definite GH raisers. I suspect some rock is sold as something is in fact is not.
 
Hi all,
hamfist said:
I must admit that I am very suspicious of any stone
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Both naming and pricing look quite aspirational for some of the stone (and wood) that you see for sale.
....... Scottish Boulders, Scottish River Stones, Elderly Boulders, Black Venom and Wild Rhino Stone are all great example of naturally eroded Stones which will accurately match the environment of a flowing river or stream .......
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I'd guess that if you buy a tonne of rock / cobbles from a wholesaler <"80-120mm Scottish Cobbles"> and then give it a "name" (I like "Black Venom", but I'm not sure which demographic it is aimed at) - <"Guide to Rocks for Aquascaping - Riverwood Aquatics Ltd"> and add "Aquascape" or "Aquarium" to the title you can imbue that rock with <"considerable added value">.

I'm not a rock buyer, but if I was, and wanted a specific rock type I would buy it from <"one of our sponsors">, you might pay a bit more but at least you know what you've got.

<"This USA based thread"> is an oldie, but a goodie <"Large rocks for large tanks">.

cheers Darrel
 
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I have some Hakki from our sponsors and it’s a lovely stone. It’s shockingly heavy compared to other stones. It’s like lifting a cast iron pan compared to a regular steel one.
 
Hi all,
Little said:
I have some Hakki from our sponsors and it’s a lovely stone. It’s shockingly heavy compared to other stones. It’s like lifting a cast iron pan compared to a regular steel one.
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<"That sounds like they really are"> <"Basalt - Wikipedia">, a dense, hard rock made of "heavy" <"mafic"> minerals. Something like <"Granite"> would be equally hard, but the high quartz (SIO2) content would make it less dense.

cheers Darrel
 
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