Why Is Alk Rising?

[aidensav]

Alkalinity in my tank has risen from 7.7 to 9.9 in about 10 days. I have a 33g tank that was set up july 4 this year. Nitrates are somewhat stable at 1 ppm. Only thing I dose is phytoplankton. I use Red Sea blue bucket, and haven’t changed buckets.
Filtration: Matrix, sponges, polyfill filter floss.
Corals look perfectly fine.

 

[tzabor10]

Are you doing water changes? How much and how often? What is the kH of your salt water when mixed?

 

[aidensav]

Are you doing water changes? How much and how often? What is the kH of your salt water when mixed?

kh of saltwater is 8. WC every week 10%

 

[RoanokeReef]

Any PH changes or running a co2 scrubber ?

 

[Mr. Mojo Rising]

IMO it is from the water changes, coral pro has higher alk than other salts. Nothing in your tank is consuming alk yet so it increases slightly without dropping.

I see the same thing in my tanks that use coral prop salt, the alk raises slightly every time I do water changes. But my alk drops constantly so I don't mind the small weekly bump.

 

[aidensav]

Any PH changes or running a co2 scrubber ?

no ph has stayed 8 and no scrubber

 

[aidensav]

IMO it is from the water changes, coral pro has higher alk than other salts. Nothing in your tank is consuming alk yet so it increases slightly without dropping.

I see the same thing in my tanks that use coral prop salt, the alk raises slightly every time I do water changes. But my alk drops constantly so I don't mind the small weekly bump.

The blue bucket has only 8 dkh

 

[Randy Holmes-Farley Verified Community Expert]

What is top off for evaporation? Tap water can contain a lot of alk.

Slow dissolution of rock and sand can slowly boost alk in very low alk demand systems.

Artificial rock can be a huge source of alk.

9.9 dKH is still fine. I recommend 7-11 dKH.

 

[Zyfreef]

Alkalinity in my tank has risen from 7.7 to 9.9 in about 10 days. I have a 33g tank that was set up july 4 this year. Nitrates are somewhat stable at 1 ppm. Only thing I dose is phytoplankton. I use Red Sea blue bucket, and haven’t changed buckets.
Filtration: Matrix, sponges, polyfill filter floss.
Corals look perfectly fine.

Alk rise usually means corals stopped consuming it so it builds up from water changes.

 

[aidensav]

What is top off for evaporation? Tap water can contain a lot of alk.

Slow dissolution of rock and sand can slowly boost alk in very low alk demand systems.

Artificial rock can be a huge source of alk.

9.9 dKH is still fine. I recommend 7-11 dKH.

top off is rodi

I used the purple dry rock and carib sea sand to start

 

[get-salty]

do you have a sump? if you do, is it internal or external drain?
if you have an internal drain, check for water evaporation in that chamber.
I've had this happened where the drain chamber all evaporated so my alk spiked. I had to close the gate valve to get water fill the chamber backup - alk slowly dropped a little.

Blue bucket alk should be 7.8 right after mix - been using the blue bucket for nearly 5yrs and they mix exactly 7.8 everytime.

Either that, bump up your water %

 

[Randy Holmes-Farley Verified Community Expert]

top off is rodi

I used the purple dry rock and carib sea sand to start

Who made the purple dry rock?

That may be the source.

Certain types of sand are also an issue. Carib Sea is not likely the issue, however.

 

[aidensav]

top off is rodi

I used the purple dry rock and carib sea sand to start

Its marco reef saver rock - Coralline

Sand is Carib Sea Special grade reef sand

There is also 5 lbs of tbs rock

 

[Randy Holmes-Farley Verified Community Expert]

DId you use anything to attach the rocks to each other? Cement anywhere?

 

[aidensav]

DId you use anything to attach the rocks to each other? Cement anywhere?

I used Instant Ocean Hold Fast Epoxy Stick for Fish & Reef Aquariums White, as well as Two Little Fishies CorAffix Coral Glue.

 

[aidensav]

do you have a sump? if you do, is it internal or external drain?
if you have an internal drain, check for water evaporation in that chamber.
I've had this happened where the drain chamber all evaporated so my alk spiked. I had to close the gate valve to get water fill the chamber backup - alk slowly dropped a little.

Blue bucket alk should be 7.8 right after mix - been using the blue bucket for nearly 5yrs and they mix exactly 7.8 everytime.

Either that, bump up your water %

I have an AIO that is auto topped off with rodi

 

[56longroof]

Have you tested the mix to verify its actually at 8 dkh?

 

[get-salty]

test the alk right after your mix.

also, check your ato system. make sure it is working correctly.

 

[Randy Holmes-Farley Verified Community Expert]

Epoxy should not significantly raise alk.

If you do not find the source, it is not that hard to lower alk in new salt water so that normal water changes can be done with low or no alk salt to keep it in check.

Here's one recipe:

https://www.reef2reef.com/threads/s...in-new-salt-water-or-in-display-tanks.362825/