Alkalinity help

austinl · Jun 20, 2017

Hey guys looking for some help here. My alkalinity has been chugging along at 7.6-7.8 for months.

I check it daily or every second day at the longest and it has gone up to almost 9.

I have not made any changes to my dosing or maintenance routines.

I make up my own mixture using aquaforest and did a top up of the dosing containers, however it was from the original mixture so it isn't two different batches.

My doser is a vertex libra and am currently dosing my 3 part at 30ml per day over 10 intervals.

My other parameters are as follows

Ph 7.9-8.2
Cal 420
Mag 1400
NO3 8
PO4 0.04
SG 1.024-1.026

Lighting schedule 8bulb ATI
6 bulbs 10 hours 4B+ 2Actinic
2 bulbs 4 hours 1C+ 1P+

Do you think this might be an equipment issue or is it possible my corals are not taking up as much alk as before?

Any thoughts?

Randy Holmes-Farley · Jun 20, 2017

Could be any of those, or more possibilities (test error, doser changing amounts dosed over time, top off water with alk in it, other things added containing alkalinity, new artificial rock leaching alkalinity, etc.).

If you have confidence in the test, i'd just dial back the dosers if you want lower alkalinity.

austinl · Jun 20, 2017

Randy Holmes-Farley said:
Could be any of those, or more possibilities (test error, doser changing amounts dosed over time, top off water with alk in it, other things added containing alkalinity, new artificial rock leaching alkalinity, etc.).

If you have confidence in the test, i'd just dial back the dosers if you want lower alkalinity.

Thanks for the quick reply Randy. I'm pretty confident in my testing and tested a newly mixed batch of water this morning and it was at 7dkh.

Nothing has been added to the tank except for some siporax in the sump (4L) are you aware of reports of alk increasing from that?

I never considered top of water from my RO containing ALK so I will test that.

I can lower my dose but would that affect my Calc and mag being that they are supposed to be dosed in equal parts?

Lastly what if any affects should inbemon the look out for with regards to my corals with the sudden increase?

Randy Holmes-Farley · Jun 20, 2017

austinl said:
Thanks for the quick reply Randy. I'm pretty confident in my testing and tested a newly mixed batch of water this morning and it was at 7dkh.

Nothing has been added to the tank except for some siporax in the sump (4L) are you aware of reports of alk increasing from that?

I never considered top of water from my RO containing ALK so I will test that.

I can lower my dose but would that affect my Calc and mag being that they are supposed to be dosed in equal parts?

Lastly what if any affects should inbemon the look out for with regards to my corals with the sudden increase?

Siporax should not impact alkalinity.
A decline in nitrate can boost alk, if that may have happened.
0-1 ppm TDS RO water won't impact alk.

I'd continue to dose both parts equally unless calcium is already too high or too low.

austinl · Jun 20, 2017

Randy Holmes-Farley said:
Siporax should not impact alkalinity.
A decline in nitrate can boost alk, if that may have happened.
0-1 ppm TDS RO water won't impact alk.

I'd continue to dose both parts equally unless calcium is already too high or too low.

My nitrates have gone down about 4ppm they were at around 12 and now show around 8 give or take reading colour charts.

TDS from RO unit reads 2ppm. Calcium is at 425 ish so I could drop it unless you think it best to keep it there.

Randy Holmes-Farley · Jun 20, 2017

austinl said:
My nitrates have gone down about 4ppm they were at around 12 and now show around 8 give or take reading colour charts.

TDS from RO unit reads 2ppm. Calcium is at 425 ish so I could drop it unless you think it best to keep it there.

That nitrate drop will only boost alk by about 0.2 dKH.

Cyricdark · Jun 20, 2017

How old is the tank and what mix of corals so you have? I've noticed in my tanks that have mostly soft corals and few sps when coralline algae really starts taking off my alk consumption will be at its peak for a few months then level off once everything gets encrusted.

Scott.h · Jun 20, 2017

Have you tested your new salt mix? You could have an oddball batch of salt.

austinl · Jun 20, 2017

Scott.h said:
Have you tested your new salt mix? You could have an oddball batch of salt.

Yeah i tested a batch this morning and it was its normal range of 7ish.

At this point I can only think of equipment malfunction being the culprit. I purchased another test kit to be sure and had a LFS test my ALK and all readings were the same within reason.

austinl · Jun 20, 2017

Cyricdark said:
How old is the tank and what mix of corals so you have? I've noticed in my tanks that have mostly soft corals and few sps when coralline algae really starts taking off my alk consumption will be at its peak for a few months then level off once everything gets encrusted.

The tank is about 6 months old, the majority of corals are sps and a few LPS down low.