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buffer top-off water?

C

cranbureefer

does anyone care what the pH is of their top-off water? I've been noticing my pH ever so slowly move from 8.3-7.8 over the course of the year my tank has been running. I just checked my top-off tank's pH... off-the-scale low, as it is distilled. So, I buffered it with some baking soda up to 8.0.

I typically test alk and calcium, and then dose the appropriate amount 2-part B-ionic. I guess I just won't have to add as much of the part 1 (alk), but I was curious: does anyone around here buffer up their top-off water? Did I just do a no-no?
 
N

NJ_ychung1

curious if you use baking soda out of the box or do you prepare it in anyway.
what was the outcome of it. did you see a measurable improvement of your PH
 
C

cranbureefer

just started yesterday, so I'll have to get back to you with the results.

All I did was dissolve a tablespoon of baking soda (directly out of the box) in two cups of RO water and then added it to the 3 gallons of distilled already in my top-off reservoir.
 
D

DaveK

If you are using RO/DI water to start with, it is not really necessary to buffer top off water. Since there is nothing extra in it, there is nothing that can effect the pH of your system.

If you doubt this, take a large volume of RO/DI water, about 50 gal, and add about a teaspoon of baking soda, and wait 24 hours. You see that this small amount of material noved the pH to about 8.2. Yet, in a reef of the same size, that amount would have little effect, due to all the other dissolved salts.

I suspect the slight drop in pH you are seeing after a year can be attributed to other factors, such as fish waste products, algae, and so on.

I think you'd be a lot better off making larger partial water changes.

It's not really wrong to buffer top off water. It's just not necessary.
 
C

cranbureefer

thanks for the advice! Good to know I didn't mess anything up, even if what I did was sort of a waste of time.

I change about 1.5 gallons a week on my 10 gallon. I haven't added any fish yet, so nitrates are 0.1 (Salifert). I guess I'll have to up the water-change percentage once the fish comes out of initial quarantine. Any algae/cyano I see seems to be contained to my aquafuge. Suppose that's the culprit?
 
V

vangvace

Did the drop occur during the winter? Or should I say became more noticed over the winter? Could be a house CO2 level then. Easiest check would be leave a window near the tank open (since the weather's nice and all right now). If that's the problem then you should see the Ph rise.

Some of my buddies back in Utah have their skimmer airline ran to the outside of the house to bring in fresh air.
 
P

pgordemer

Officer Emeritus
Officer Emeritus
Testing PH in RO/DI water with a TDS near zero is almost impossible to do with any accuracy, since there aren't enough ions to get a correct reading. The equipment needed to test for it is very expensive.

Since there are almost no ions, the water will take on the PH of whatever it is mixed to.
 
C

cranbureefer

pgordermer: that's a good point about testing pH in water that is 0 TDS. Didn't think about that...

vangvace: I'm not thinking it's the closed room thing, as I'm noticing the pH continuing to drop even now in the spring when I leave the windows open.

Edward771: the article doesn't really say *why* we should "bake" the baking soda. I understand that it drives the water away, but who cares? It's going into water, isn't it? If the CO2 that the baking removes is a problem for pH reasons (i.e. with C02 the baking soda wouldn't raise pH as much), I would just add more baking soda! Or is that bad...
 
V

vangvace

What is your Alk and Calcium reading BTW? I normally dose kalkwasser after 6 months or so depending on the tank's needs and use baking soda as necessary for my alk.

How is your water circulation BTW? too little surface movement could cause ph to lower as well.

To answer your baking soda vs baked baking soda (aka washing soda):


Baking soda and washing soda both add carbonate alkalinity to the water. Baking soda will have a tendency to lower the pH when initially added. Washing soda will have a tendency to raise the pH when initially added. They both will eventually stabilize at a good pH if your tank has good circulation. A mix of 5 parts baking soda and 1 part washing soda has an almost unnoticed effect on tank pH. If you can't find washing soda you can make it yourself by spreading baking soda out on a cookie sheet and baking it at 300 F for an hour or two. This method works great. I use straight baked baking soda for alkalinity adjustments. I would not suggest raising alkalinity by more then 1.5 to 2.5 dKH per day. Approximately 5 teaspoons of washing soda will increase 100 gallons of water by 3 dKH.

Baking Soda -> sodium bicarbonate -> NaHCO3

Washing Soda -> sodium carbonate -> Na2CO3

In your tank water there is an equalibrium between carbonate and bicarbonate:

CO2 + H2O = H+ + HCO3- = 2H+ + CO3--
low pH = mid pH = high pH

So from an alkalinity prespective there is little difference between washing and baking soda, but there is a difference in pH effect.

Oh and adding too much soda to your tank can cause calcium precipitation (snowstorm) in your tank.
 
C

cranbureefer

so washing soda = baked baking soda? cool.

I keep my calcium at 440 and alkalinity at 4.0 meq/L. I test after each water change and then dose over the following week with B-ionic two-part.

I have about 60X flow in my 10-gallon, but I wish I had my surface-skimmer still running. That could be the problem. I used to have it attached to the powerhead that feeds my refugium. Took it off due to tank real estate shortage. There's a little bit of "stuff" floating on the water now, but the koralia's keep it churned pretty good.

I can keep the calcium and alk pretty stable... have never tested magnesium. Would that make any difference?
 
V

vangvace

Testing magnesium wouldn't hurt, but if it were low you would most likely have issues keeping Alk or Ca. stable. I'd call your lfs and see if they'll test it for you and then decide to buy a kit from there.

How still is the water's surface? Might have to adjust one of your powerheads more surface bound to really mix it up. Does the stuff kinda look oily?

How long after water changes are you testing? Have you checked your Ph in the morning? (like 6 AM-ish) That's when you Ph will be at it's lowest assuming you aren't running a RDP.
 
J

Johan

Another ph factor that I have seen before that would drop your ph would be your skimmer is not working or up to par with the bio load..
 
C

cranbureefer

No skimmer, Johan... just water changes.

vangvace: I typically test just after doing a water change. Is that bad? My surface is pretty wavy. Most of the stuff floating on top of the water just looks like little specks... not so much "oily".

One of my old snails died yesterday. I saw the hermits munching on him. My candy-cane has been finicky lately, sort of shrunken. I have caught my peppermint shrimp snacking on him. Not good.
 
V

vangvace

I'd recommend waiting at least an hour after the water change to test. This'll help make sure that the old and new water is mixed. It should be fine to test soon after doing the change, but I like using caution. Before your next water change check your Ph in the tank. Then check it again after to see if the change made any improvements.

Does the tank currently have a refugium? Is it's lighting cycle the middle of the night or while the main tanks lights are on? (nothing to do really with the topic at hand just curious for once we get your Ph raised)
How large of a water change do you typically do?

For the heck of it. Move the powerhead on the left hand side of the tank up a smidgen (1/2" at most) just to get a little more turbulence along the water surface. Are you seeing alot of shimmer in your tank from the metal halides or is it mostly solid?

Sorry if this post isn't well organized.
 
C

cranbureefer

lot's of shimmer from the halide, for sure. I'll try to raise one of the koralias a tad, but I'm trying to keep from getting a whirlpool (happens when I'm changing the water and the level is near the powerhead).

I'll definitely try testing pH before and after my water change. I wish I hadn't bought the salifert pH kit... what a piece of trash! goes from 7.7 - 8.0 - 8.3 with no steps in between. I liked the pH test in the seachem multi-test WAY better.

My 2.5 gallon CPR aquafuge runs opposite the rest of the tank's lighting. Here's the schedule:

blue moonlights on all the time
1 pm white moonlights on (Sunpod fixture)
2 pm 150W 14k halide on
10 pm halide off
11 pm white moonlights off, fuge lighting on (Coralife, 18W of PC)
1 pm fuge off, white moonlights on, etc.

so, the fuge is lighted from 11 pm - 1 pm and the halides are on from 2 pm - 10 pm
 
C

cranbureefer

well, here we are...

Now my alkalinity is 4.0 meq/L, but my pH is 7.8. Should've baked the baking soda into washing soda, I guess, before adding it to my top-off. Will try that NEXT time...

Still no word as to why my pH is so low. I have the koralia nanos stirring up some serious surface water, run my fuge opposite my tank lights, and the windows in my apartment are open!

Other parameters are fine: 79 degrees, 1.025 sg, 380 ppm calcium (typical for end of week... will dose to 440), 4.0 meq/L kH (usually I dose with to part to get to this number... already there thanks to the baking soda in the top-off water), 0.5 nitrate.

Any suggestions? I would like a higher pH, but does it REALLY matter? I tested this today just before the halides went on (just after turning off the fuge lighting). I test an hour after changing the water, now.
 
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