Bew Reef - Alk crash

[gfinnerz]

Hello

Quick intro - I set up a waterbox 35.1 cube (sumped) end of June, cycled for four weeks using fritzzyme plus ammonia chloride, and fully cycled the tank. Dosing 2ppm ammonia down to 0 within 24 hours.

I bought a pair of captive clowns on Sunday and put them in the tank, they're feeding and happy.

The issue i have is that my tank was running around 10.5 dkh and 8.2ph on 14/7 and the day I bought fish was also around 10. I performed a 30L (30%, full tank with rock and sand is ca. 100L) waterchange the day before I bought fish and LFS confirmed high alk still. (I'm using red sea blue bucket so mixes around 8dkh

Fast forward to Tuesday testing (yesterday) - my alk had crashed to 6.5 and Ph around 7.4. There are some white deposits in the sump which I assume might be precipitate, but ununsure. I mixed another batch of saltwater overnight so planning to do a 30% w/c again shortly

Can anyone think of a reason for:

1) the elevated alk levels in the first place when using blue bucket (I have fiji pink live sand plus my rock is DD aquascape natural)

2) the huge alk crash plus the ph drop?

Recent tests as of yesterday:

Alk 6.5
Ph 7.4
Ammonia 0ppm
Nitrate 10ppm
Salinity 1.024 (while fishless, will raise up to 1.025 when corals are added)
Temp 78F

Ca haven't tested yet
Mg haven't tested yet

Thanks!

 

[Randy Holmes-Farley]

water changes are a very expensive way to boost alk. Just dose baking soda in this situation.

I cannot say if the results are accurate, or if they are, why alk declined, but if testing shows alk below 7 dKH, I’d at least boost it to 7 dKH with baking soda.

 

[gfinnerz]

Hey Randy

Thanks for the input. I tested the same result around 5 times and the LFS matched mine (red sea & salifert) - puzzled at the drop. I don't have a huge amount of experience and I've not tested mg or ca but I can only assume there was some precipitation. Alternatively I'd only just added two new fish post cycle, perhaps there was some consumption as more ammonia was produced than had been over the last month during the cycle. But that much of a drop seems excessive

I don't have corals and won't for the next few months as I run lights off - but trying to train good husbandry from the start regardless.

From reading your reef chemistry series previously iirc I can recall reading that baking soda will have minimal impact on ph (slight reduction but correction later on once mixed) whilst soda ash will 'bump' both. Given my ph is reading 7.4 with 'ideal' ph around 8.2, is it worth dosing soda ash to boost both other a week period rather than baking soda (bicarb)?

Thanks
Cam

 

[Randy Holmes-Farley]

Hey Randy

Thanks for the input. I tested the same result around 5 times and the LFS matched mine (red sea & salifert) - puzzled at the drop. I don't have a huge amount of experience and I've not tested mg or ca but I can only assume there was some precipitation. Alternatively I'd only just added two new fish post cycle, perhaps there was some consumption as more ammonia was produced than had been over the last month during the cycle. But that much of a drop seems excessive

I don't have corals and won't for the next few months as I run lights off - but trying to train good husbandry from the start regardless.

From reading your reef chemistry series previously iirc I can recall reading that baking soda will have minimal impact on ph (slight reduction but correction later on once mixed) whilst soda ash will 'bump' both. Given my ph is reading 7.4 with 'ideal' ph around 8.2, is it worth dosing soda ash to boost both other a week period rather than baking soda (bicarb)?

Thanks
Cam

Repeated testing doesn’t ensure accuracy, but the current value may be right and the previous one was wrong. Or both may be right. But freak results are more often testing issues than freak events.

That said, boosting the alk is a fine plan and trying to figure out why alk declined is likely not going to be fruitful. :)

I don’t believe pH 7.4 is accurate, but aeration with normal air will raise it to 8 if it is.

No alk additive is going to make a long term (more than a day) effect on pH from a single corrective dose, but it is also fine to use sodium carbonate if you want. I would not recommend getting into hydroxide dosing at this point unless you want to begin using limewater/kalkwasser.

 

[Bruttall]

Easy way to boost PH is to add air stones to a Non Display part of your tank.

My filter system:


Air Pump feeding Air Stones in my sump:

Ph chart off my Apex, you can see for yourself how consistent that Air Stone method is for maintaining PH. I dose All4Reef to maintain DKh.

 

[gfinnerz]

Thanks both.

Will adjust with carbonate and not worry too much about the drop. Will have a look at testing equipment and also airlines

Appreciate it

 

[Uncle99]

Thanks both.

Will adjust with carbonate and not worry too much about the drop. Will have a look at testing equipment and also airlines

Appreciate it

I seem to get fluctuating results on Alk and CA if my MG runs to low.

I’d get MG up to 1350-1400ppm, ensure salinity is 35ppt, then retest Alk again.

it’s best to run a dkh which is stable, rather than any specific number, but, still has to be in the range say 8-11.