What caused low alkalinity in cycling tank?

[mossmoss]

i took my water to get tested at the shop, hoping my live rock tank would be ready for fish. Shop keeper said my alkalinity was SUPER low. (4?) She sold me KH buffer to dose daily and a test kit.

The dosing seems to be working well but I would like to know how this happened.

The only change I made to my tank was the addition of an Aquaclear HOB filter and wasnt aware that I shouldnt put in the included filter media. The filter was running with the foam, carbon and biomax for about a week. Could this be the cause?

Thanks!

 

[Miller535]

i took my water to get tested at the shop, hoping my live rock tank would be ready for fish. Shop keeper said my alkalinity was SUPER low. (4?) She sold me KH buffer to dose daily and a test kit.

The dosing seems to be working well but I would like to know how this happened.

The only change I made to my tank was the addition of an Aquaclear HOB filter and wasnt aware that I shouldnt put in the included filter media. The filter was running with the foam, carbon and biomax for about a week. Could this be the cause?

Thanks!

No, those things would have no impact on ALK. Did you happen to test your water when you first made it? Did your LFS check your salinity ?

 

[ColdOceanReef]

You should test Ammonia, Nitrites and Nitrates. With that your ALK is low. What salt are you using and what is your salinity level.

 

[lapin]

Test salinity first . Most salt mixes are at 7 or above when mixed to 1.025. Your tank could be using alk while things grow. Since you used live rock, it may have coralline and other alk consumers. A water change should bring it back up without the need for a buffer.

 

[W1ngz]

It is normal for alkalinity to drop during the conversion of ammonia to nitrate. As the tank matures, the effect will lessen as It will be partially returned during de-nitrification later on.

Dose what you need to, but don't blindly keep dosing just because the store said to or you'll end up with the opposite problem.

You really should start doing your own testing now that you've reached the end of your cycle, instead of remaining tied to your store. They should be helping you develop these basic skills, not doing them for you.

For anyone who wants more detail, look about half way down this page for Alkalinity Decline in the Nitrogen Cycle

 

[mossmoss]

It is normal for alkalinity to drop during the conversion of ammonia to nitrate. As the tank matures, the effect will lessen as It will be partially returned during de-nitrification later on.

Dose what you need to, but don't blindly keep dosing just because the store said to or you'll end up with the opposite problem.

You really should start doing your own testing now that you've reached the end of your cycle, instead of remaining tied to your store. They should be helping you develop these basic skills, not doing them for you.

For anyone who wants more detail, look about half way down this page for Alkalinity Decline in the Nitrogen Cycle

I am doing my own testing. I have trouble reading the ammonia test and the shop keepers have not been very helpful in answering questions about determining test results.

I am still learning so I do not trust the accuracy of reading my own test results.

A couple times I thought my ammonia was 0.15 and shop keeper said it was at 1 so I often leave confused.

The shop wont sell fish to me until they deem the tests safe/ tank cycled so I have to have them test my water to confirm my tests.

I had only been testing ammonia, nitrite and nitrate before... didnt realize I needed to track the alkalinity as well so i am doing that now.

Shop keeper acted very shocked that my alkalinity was so low but didnt offer any reasons why it might be so Im just trying to piece it together.

thanks for all the input
¯\_(ツ)_/¯

 

[mossmoss]

Test salinity first . Most salt mixes are at 7 or above when mixed to 1.025. Your tank could be using alk while things grow. Since you used live rock, it may have coralline and other alk consumers. A water change should bring it back up without the need for a buffer.

I buy pre made salt water from the shop. I test salinity with a refractometer and it has been steady at 1.025/1.026 since i started the tank 3 weeks ago.

I did a 10% water change 4 hours before bringing my water into the shop. Is that enough time for accurate readings?

 

[NS Mike D]

the hobby test kits can be lousy. I am in the camp that you only need to test for NO3 (with a reasonably reliable test kit like red sea, seifert, hanna etc. When NO3 is testing positive, the tank is cycled. Some believe that all you need to do is wait 30 days and the tank will be cycled. Cycled is not the same as mature and why we recommend to add things slowly to give the tank the chance to get back in balance quickly.

I have no explanation why your Alk is at 4 (dkh I presume), so I will take a pass on that.

 

[NS Mike D]

I buy pre made salt water from the shop. I test salinity with a refractometer and it has been steady at 1.025/1.026 since i started the tank 3 weeks ago.

I did a 10% water change 4 hours before bringing my water into the shop. Is that enough time for accurate readings?

the shop water might have had a precipitation event prior to selling it to you. Precipitation is when the ALK starts combining with the Calcium (which is what the corals to to build skeleton) and forms a solid (most commonly we see it as the teeny rock spheres that form on the pumps and other hard surfaces). FYI, mg keeps the ALK and CA separated in solution. At 4 dkh, that should have prompted him to double check his supply, IMO.

 

[Randy Holmes-Farley]

the hobby test kits can be lousy. I am in the camp that you only need to test for NO3 (with a reasonably reliable test kit like red sea, seifert, hanna etc. When NO3 is testing positive, the tank is cycled. Some believe that all you need to do is wait 30 days and the tank will be cycled. Cycled is not the same as mature and why we recommend to add things slowly to give the tank the chance to get back in balance quickly.

I have no explanation why your Alk is at 4 (dkh I presume), so I will take a pass on that.

Nitrite shows as a big false positive on many nitrate kits. So seeing nitrate isn’t a reliable indicator of a completed cycle.

 

[Randy Holmes-Farley]

I buy pre made salt water from the shop. I test salinity with a refractometer and it has been steady at 1.025/1.026 since i started the tank 3 weeks ago.

I did a 10% water change 4 hours before bringing my water into the shop. Is that enough time for accurate readings?

it takes almost no time for the alkalinity to mix up and even out.

cycling lowers alk as nitrate is made from ammonia. When it gets low, just boost it with baking soda.

 

[NS Mike D]

Nitrite shows as a big false positive on many nitrate kits. So seeing nitrate isn’t a reliable indicator of a completed cycle.

thanks for that clarification, I was informed that other than the seneye nitrite test (ridiculously expensive) those test are notoriously wrong and thus creating the false notion that cycles can stall.


So other than the passage of time or spending $$$ on seneye tests, what do you recommend?

 

[Randy Holmes-Farley]

thanks for that clarification, I was informed that other than the seneye nitrite test (ridiculously expensive) those test are notoriously wrong and thus creating the false notion that cycles can stall.


So other than the passage of time or spending $$$ on seneye tests, what do you recommend?

I've not evaluated nitrite kits to have a specific recommendation.

 

[W1ngz]

I don't beleive Seneye has a nitrite or nitrate test. They cover ammonia, ph, temperature and light.

 

[mossmoss]

ok, so i just realized.. i was told not to use tap water to rinse or clean anything i used in the tank; I was told to use vinegar instead. Before I did my water change I rinsed the pyrex measuring cup (that i use to remove tank water) with vinegar to eliminate potential of any soap/tap water residue etc. from last time I used it. Could having some trace amounts of vinegar in the tank lower the PH in my 20g tank significantly?

 

[Intense37754]

Vinegar will lower Ph, significantly I don’t know for sure. But I did clean powerheads once and ph dropped and had to add an airstone because I didn’t rinse off in plain RO.

I personally never use tap water on anything going in the tank for the sand reason we use 0 TDS RODI

 

[Randy Holmes-Farley]

ok, so i just realized.. i was told not to use tap water to rinse or clean anything i used in the tank; I was told to use vinegar instead. Before I did my water change I rinsed the pyrex measuring cup (that i use to remove tank water) with vinegar to eliminate potential of any soap/tap water residue etc. from last time I used it. Could having some trace amounts of vinegar in the tank lower the PH in my 20g tank significantly?

No.

 

[Randy Holmes-Farley]

From my high pH article I tested the effect of vinegar. 1 mL per gallon drops pH by 0.3 pH units. I assume a trace of vinegar is far, far less than 1 mL per gallon so the effect is small. The effect is also temporary and will be gone in 24 h.

 

[mossmoss]

From my high pH article I tested the effect of vinegar. 1 mL per gallon drops pH by 0.3 pH units. I assume a trace of vinegar is far, far less than 1 mL per gallon so the effect is small. The effect is also temporary and will be gone in 24 h.

ok, thank you, thats really good info. i guess i will assume the low ph was part of the cycle and the LFS really shouldn't have advised to dose the KH buffer before testing over a couple days to get a good picture of what was happening.

I dosed the buffer 3 days and finally learned how to use salifert test properly (thanks YouTube) ... it is now reading 10.5 ¯\_(ツ)_/¯

 

[Reef.]

Why not just use rodi water to rinse equipment? Must be cheaper, as a bottle of vinegar can’t go very far.

I’m having the same issue with low alk, not sure what’s causing it either.