PH increase from 6.2 to 7.8 after adding 10 lave rock...

[adidasvintage]

Hi,

Recently measurred my tank's PH to be around 7.8. It was around 6-6.6 in the past.
The only difference is the recent addition of 10 lave rock(size diameter about 4cm each)
Current water parameter:
PH 7.8
GH 8, KH 3
Amm 0
Nitrite 0.25 (can never hit 0)
Nitrate 20ppm
Phosphate 1ppm
Using ADA amazonia as substrate, CO2 injection with DC green color. Tank size is 422 - 120gallon.

I would like to know how can I get my PH back to between 6-7 range and both GH/KH to 3? I intend to add in more lava rocks soon but seeing the increase in PH and maybe GH, I was scared. If the PH & GH remains at this level any effect to plants/fish?

[Urban Aquaria]

There are many different types of lava rocks and not all are inert... many still have residual minerals still trapped in them which may gradually release over time.

But in your case, you have a 120 gallon tank which should have more than enough water volume to counteract the pH/GH/KH increasing effects of just 10 small pieces of lava rocks.

Perhaps you could remove those lava rocks and place them in a container of water for a week or so, test the water before and after and see if its really those lava rocks which are affecting the water parameters.

[adidasvintage]

BTW, before introducing those rocks, about 1-2 weeks before, I started dosing with Lushgro Aqua and Calcium Nitrate. Could the Calcium & Magnesium in this 2 fert be the main cause instead?....

[Urban Aquaria]

BTW, before introducing those rocks, about 1-2 weeks before, I started dosing with Lushgro Aqua and Calcium Nitrate. Could the Calcium & Magnesium in this 2 fert be the main cause instead?....

I've not used those particular brands of ferts so can't comment on them, perhaps others who have used them will share their experience.

But i would think that fertilizers causing such large pH/GH/KH changes would be very unlikely (seems rather counter productive if a fertilizer shifts water parameters further away from favorable conditions for plant growth). If they do have that effect, i'd guess the manufacturer would have indicated it very clearly on the fertilizer bottles, as that is quite a significant change in water chemistry.

Maybe check your tap water parameters? If you are using tap water for water changes, its possible the tap water pH could have somehow increased recently, and that could in turn affect the pH in your tank too.

[AQMS]

yes, Calcium Nitrate will increase the PH.

[Urban Aquaria]

yes, Calcium Nitrate will increase the PH.

Interesting... would it increase pH that much even at recommended dosages? I'd imagine it would need to be quite a high dosage to offset the pH/kH buffering ability of ADA Amazonia aquasoil + Co2 injection.

[Dodofish]

My ph for tap water went up to 8.4. You may want to check yours.

[AQMS]

Interesting... would it increase pH that much even at recommended dosages? I'd imagine it would need to be quite a high dosage to offset the pH/kH buffering ability of ADA Amazonia aquasoil + Co2 injection.

You have a point there. Im not sure about dosage cause i never try it before.

[adidasvintage]

Did some test and confirm that the ph increase is due to the lava rocks. Tap ph > 7, isolated rock in tap water after 1 day in a small container is ~8+...
Should I discard those lava rocks? Noticed my tank ph is around 6.6-7 after 6 hrs of co2 injection and ph-8 before co2 timing. i find the differences a bit huge.
i also intend to add more black lava rocks to my scape in near future any suggestion how can I get rocks that do not increase ph so greatly? I fun think I can do vineger text at any lfs tight?

[AQMS]

Lava rock is inert and should not cause any ph fluctuation.
Are you sure it is lava rock?
Pour some vinegar on it to see if it fizzes, or stick it in a bucket with RO and measure if there's a difference in ph/kh/gh after a day or two.
If Vinegar, which has pH 4.5 or so, doesn't cause any reaction in the rock, then chances are, your tank water won't either.

[adidasvintage]

Those are lava rocks bought and confirmed from polyart.... It's a package of smaller pieces. Maybe need to buy from other places and confirm again.

[seudzar]

Lava rock should be inert. For your case, the surface of the rocks may come in contact with other type of rocks during handling which results this. You might want to soak the lava rocks for a week or 2 to leech out those minerals first before putting them into your tank