Alkalinity questions

[AZBigJohn]

With my tank reboot, I have been watching my numbers closely. I have two problems - Excess phosphate (which I know, and am battling with a GFO reactor). I also seem to always have a dkH in the low 6 region. I know most don't track pH, but mine is low at 7.6.

Where do you keep your dkH, and where does your pH stay? What if any supplements do you use to keep it there? (I use limewater as my ATO).

Is there a good way to bring up dkH alone? My calcium is fine at 450, and my mag is still a little high from my Kent M treatment, sitting in the 1700 range.

 

[AZBigJohn]

Guess I should put all my parameters out there:

As of 12 noon - (I use a refractometer, Red Sea tests except for Magnesium (Salifert) and Phos - (Hanna checker))

Temp 78.7
Specific gravity 1.026 - refractometer
pH 7.6 -
Alk 6.2 dkH -
Ammonia - undetectable -
Nitrite - undetectable
Nitrate - undetectable
Phosphate 0.21
Calcium 450
Magnesium - by dilution - between 1700-1800

 

[Nibrown9]

I run my alk at 7.8-7.0 what you can do to raise alk is use baking soda...dilute 2 table spoons in 3 cups of rodi and add half cup 2x a day. This will slowly raise dkh...as for ph you need to ald more kalk since adding baking soda will drop ph..

What do you plan on stocking with corals?

i learned to stop chasing numbers and learned to read the corals since chasing numbers made me tweak and tinker to much causing instability

 

[Rippinfrags]

I'm surprised your alk and ph is so low. Lime water should be correcting both of those issues. Maybe try strengthening your concentration of lime water. Like Nibrown said I wouldn't worry about chasing numbers. However, corals grow best when parameters are stable.

 

[AZBigJohn]

I'm surprised your alk and ph is so low. Lime water should be correcting both of those issues. Maybe try strengthening your concentration of lime water. Like Nibrown said I wouldn't worry about chasing numbers. However, corals grow best when parameters are stable.

That might be the key. I usually dump Mrs. Wages pickling lime into the ATO water and stir, but I have never really carefully measured it out to make sure I am forming a totally saturated liquid.

 

[SkullV]

That might be the key. I usually dump Mrs. Wages pickling lime into the ATO water and stir, but I have never really carefully measured it out to make sure I am forming a totally saturated liquid.

If you are dumping the Kalk in then it is probably fully saturated. The RODI will only take ~2tsp/g into solution and all the rest of the Kalk will sit at the bottom of the ATO container. A lot of people do their ATO this way and give it a quick stir every time they fill up to allow the new water to become saturated. Just make sure to keep your pump inlet up and out of the layer of unused Kalk. You can add vinegar to the RODI solution to allow it to accept additional Kalk but that is almost always unnecessary and can cause more harm than good.

Unless you have a tank full of huge clams or huge SPS colonies than fully saturated Kalk should easily make up for your Alk/Cal needs, especially with the heavy evap out here in the desert. My recommendation would be to get another high quality test kit to compare with yours. I have a Salifert in Gilbert if you want to stop by with some water.

As far as pH, is your house all closed up with the AC on or are you opening your windows this time of year? Low pH is common in homes/spaces that are all closed up because every animal in the home is breathing in the oxygen and breathing out Co2. This could also be caused by the lower than normal dkH though. Either way, I agree with nibrown9, don't chase numbers and let the coral do the talking.

 

[AZBigJohn]

House is closed up tight with a wonderful (but hormonally challenged) wife, with the air on full! I am sure that has something to do with it (Currently my 1100 sq foot house has three adults and a child living here, with a huge dog, too)

I agree with not chasing numbers, but as I just put my first few frags of SPS in the tank after the auction, I want things to be as good and stable as possible to give them a chance to thrive before I have to start watching for changes (or unhappy coral).

Thanks for the advice and information about the kalk...

If you are dumping the Kalk in then it is probably fully saturated. The RODI will only take ~2tsp/g into solution and all the rest of the Kalk will sit at the bottom of the ATO container. A lot of people do their ATO this way and give it a quick stir every time they fill up to allow the new water to become saturated. Just make sure to keep your pump inlet up and out of the layer of unused Kalk. You can add vinegar to the RODI solution to allow it to accept additional Kalk but that is almost always unnecessary and can cause more harm than good.

Unless you have a tank full of huge clams or huge SPS colonies than fully saturated Kalk should easily make up for your Alk/Cal needs, especially with the heavy evap out here in the desert. My recommendation would be to get another high quality test kit to compare with yours. I have a Salifert in Gilbert if you want to stop by with some water.

As far as pH, is your house all closed up with the AC on or are you opening your windows this time of year? Low pH is common in homes/spaces that are all closed up because every animal in the home is breathing in the oxygen and breathing out Co2. This could also be caused by the lower than normal dkH though. Either way, I agree with nibrown9, don't chase numbers and let the coral do the talking.

 

[evolved]

I also seem to always have a dkH in the low 6 region. I know most don't track pH, but mine is low at 7.6.

As you know, low 6's is too low on Alk.
There's also an Alk/pH relationship; higher alk generally equates to higher pH (or at a minimum easier to maintain a certain pH level).

Fix the alk, and you'll probably find pH is better maintained too. (and this is also why those who chase pH numbers are scary as all pH "boosters" also raise alk. And typically those people chasing pH boost alk way off the charts before they realize something isn't right)

Considering using a soda ash solution to raise alk; it will also raise pH (it's very basic in pH, whereas baking soda is not).