pH swings

[Hadakiri]

I just got into the hobby; I have a 120 gallon tank with a SWC 160 skimmer. I also have a pH probe connected to my AC jr. My pH runs at 7.98 in the morning and at night it goes down to 7.67. I have the skimmer air inlet connected to a tube that leads to outside my window. How can I keep a constant pH above 8.0 without having to dose. I only use Tropic Marin Pro reef salt. Seems to my like their numbers are on the low side or something. My Alk is 7, Phos 0.03, Nitrate 0. Any help or comment would be greatly appreciated.

 

[Boomer]

How can I keep a constant pH above 8.0 without having to dose.

You can't, your tank is not the ocean, where buffers are always being added/dosed Right now your issue not buffers but to much CO2, which is why the pH is low.


Try to read through this

Low pH: Causes and Cures
http://reefkeeping.com/issues/2004-09/rhf/index.htm

 

[Hadakiri]

So is there no way around it, Do I have use 2 part dosing?

 

[Boomer]

You have to measure your daily or at lest weekly needs for Alk and Calcium to see how much to dose.

So, for example

Week 1

Alk 8
Calcium 420


Week 2

Alk 7.5 Alk

Calcium 410

So, you have to add back in once / wk 0.5 Alk and 10 ppm Calcium to get it back to 8 and 420. This is done with -part. However, if the Calcium stayed at 420 and the Alk went to 7.5 then just add back in the 2 part for Alk. If your system can handle it you can just drip in daily Kalk water, usually at night and this also corrects for evaproated water.

 

[Hadakiri]

Thanks for clarifying things.

 

[46nBliss]

RODI water also has a low PH so when that is setup to your topoff it could bring the PH down. I buff the Toppoff water and it keeps my PH above 8

 

[Hadakiri]

Ok stupid question what do you buff your topoff water with?

 

[46nBliss]

http://www.marinedepot.com/Seachem_...ements-Seachem-SC1333-FIADPKDP-SC1337-vi.html

Im using a aqua lifter pump for my ATO so it fills the sump or tank slowly when evaporation occurs.

People also use KALK to maintain PH levels with Calcium. its a more advanced method needs to be added slow slow slow or else you can have a swing that can effect your tank.

It needs to be dissolved in fresh RODI water before added.

 

[Hadakiri]

Thanks for the link didn't know this product existed. So if you add the buffer to your topoff how long does it stay stable? Or do you see that over time it drops off. The reason I'm asking is because I have a 30 gallon top off and doesn't get all used up until 2 wks. So if I add to my top off will it remain in solution and continue to be potent for that long?

 

[46nBliss]

I'm reading on RC people debating whether or not to buff RO water. I guess if your tank needs PH up you can buff it with something like seachem or KALK. But once your ph levels are good and steady there is no need to use it anymore as the RO low PH pure water will change to 8.3 when mixed with the tank water.

i would think it would maintain the PH as long as its getting air mixed with it.

I'm going to start using KALK to maintain calcium/ph and then poof no more debate.

 

[Hadakiri]

ok thanks for your help. I think I will try and see how it goes.

 

[Boomer]

Bliss, yes that is true there is no need to buffer RO/DI water. Think of it this way. Water is evaporating from your tank and that is why you top it off. When water evaporates it does not take buffer with it but leaves it behind. However, a buffer like Kalk is often added to the TOW-RO/DI water as the tank is loosing Alk to corals, others and abiotic precip. So, this is a good way to keep the buffer /Alk/pH up. Now, if you are supp'ing by some other means there is no reason to buffer TOW.

i would think it would maintain the PH as long as its getting air mixed with it.

Air may be a good thing or bad thing it depends on the room air CO2. If the room air CO2 is high it can lower the pH, not raise it.

 

[Hadakiri]

Makes sense. thanks. I'm not supplying Kalk in other way because at the moment I only have one LPS coral in my tank along with 3 fishes. ( Yellow tang and 2 chromis).

 

[46nBliss]

Gotcha boomer thanks for the info.

 

[Boomer]

Ok

 

[henrystyle]

Open a window. works everytime.
Tanks need fresh air.. No air = low ph. The difference is noticeable right away.

 

[ReeferMadness99]

If the skimmer does not provide enough air/volume, then running in intake from outside will not be adequate. Is your tank closed on top? Providing more open surface area allows more CO2 to escape from the system. Also, a slightly cracked window will help tremendously.

 

[ravi197699]

mine had same problem then i added calcium reactor out to my aquac ev120 and the takes out access co2 out of water that drips out of the reactor and goes through my skimmer and then in the sump and now my ph level stays between 8.00 to 8.4

 

[CaptiveReef]

Use a 2 part calcium/buffer or dose Kalkwasser

I just got into the hobby; I have a 120 gallon tank with a SWC 160 skimmer. I also have a pH probe connected to my AC jr. My pH runs at 7.98 in the morning and at night it goes down to 7.67. I have the skimmer air inlet connected to a tube that leads to outside my window. How can I keep a constant pH above 8.0 without having to dose. I only use Tropic Marin Pro reef salt. Seems to my like their numbers are on the low side or something. My Alk is 7, Phos 0.03, Nitrate 0. Any help or comment would be greatly appreciated.

The end product of filtration is the production of acid, water changes will help with the addition of calcium and the buffering of the water, but you will have to maintain the calcium/buffering of the tank by using a 2 part calcium/buffer, or dosing Kalkwasser at a rate of 1 pint per 50 gallons per hour, or using a calcium reactor. I have a 120 gallon tank with a 15 gallon sump, my tank evaporates at a rate of 1 gallon per day, I top off the evaporated water with kalkwasser and I dose a 2 part calcium/buffer the day I do a 10 gallon water change once a week I add it with the new salt water. This maintains the calcium, alk, ph, also remember your tanks ph will drop at night due to the production of co2 from algae.

Hope this helps
CaptiveReef

 

[wschang812]

I heard chaeto helps with pH swings on a reverse light cycle in the refugium. Not positive though.