Perpetually low PH

[tsr770]

I have a 95 gallon tank with a basement sump that holds about 80 gallons of water.
I have been fighting my PH levels ever since I set the tank up, right now it has steadied out at about 7.65, my fish dont really mind it, but my corals are suffering.
Water changes boost it up to about 8.1 for a few days, but it always works it way back down to 7.6ish. All top off is done via a perilistic pump with kalk water, I have seen little to no difference in PH since starting the all kalk top off, although my alk now stays at about 10kh and my calcium tests at 460-480 every time.

I have used 2 different PH meters and a Salifert test kit for the PH and they all say the same thing, so it isnt a faulty test kit.

One thing I was curious of for short term use is if baked baking soda will help me bring it up some untill I get the cause of the low PH figured out.

The other thing is if anyone has any idea of what could be causing my PH to be so low. The only thing that I can possibly think of is that my basement that contains my natural gas furnace, water heater, and dryer possibly has a high CO2 level and that is being mixed in the water by my skimmers air inlet.
Would piping air in from outside possibly solve my problem?

If anyone has any input please do.. I am about at wits end with the tank at the moment.

Thanks in advance.

Josh

 

[Percula9]

Bringing in outside air will surely help. Take some water out and bubble for an hour and see if the pH comes up. If it comes up significantly then CO2 is the problem. Try a straight kalk drip directly into the sump. A refugium would help the pH by absorbing the CO2 in the water.

 

[aqua1206]

same problem

same problem

I to have a low ph problem.. and my 120 gal tank is in the same room with 2 hot water tanks and furnace.. I have a 40 gal refugium and a mr3 skimmer w mag 24 pump in a 30 gal sump. My alk is 4.7 and all my other perimeters are good. I never thought about co2 I am going to try outside air. I'll let you know...

 

[Randy Holmes-Farley]

Yes, low pH is usually driven by CO2 in your home air, sometimes just CO2 in your tank.. More fresh air and using limewater are the best options.

This article has more:

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

 

[rick s]

Hi Josh,

I also have gas appliances so I “feel your pain.” Connecting an outside airline to my skimmer helped some. I also open my kitchen window anytime the gas oven is on.

You have a lot of gas appliances in a (basically) closed room, with your sump. When natural gas or LP gas is burnt, it produces CO2. Anything with a pilot light is going to be part of your problem. That is at least the hot water heater, and possibly the furnace if it’s an older model. With just a pilot light burning, there is not enough heat to cause the burnt gas to rise up the flue/chimney and out of the house, so at least some of it (my theory) lingers around your basement.

But, even the appliances with electronic ignition can put CO2 into the room. Sometimes when they’re running the draft is not as strong as it could be and sometimes, wind can cause a backdraft.

If you also have a gas range/stove/oven upstairs, CO2 is heavier than air. So its output can also end up in your basement.

Is that enough bad news for one day? Sorry.

It might pay to have your chimney checked out/cleaned. For your tank’s health and yours. If a pipe has collapsed or is clogged, you would want to know.

If the basement is unfinished and not used, opening a window should help. Although being in Michigan, during the winter that wouldn't be a good option.

Connecting an outside airline to your skimmer should help as that adds oxygen to your water. But it will still be competing with all that exposed tank water.

Another suggestion would be to add even more outside air by running an air pump located outside to an airstone in the sump. At a minimum, rigging these up temporarily would show you what effect they have. If it helps, then you could make it permanent (pretty).

Something else I did that helped me is changing how I added my kalk. I used to do it as top-off water also with a gravity fed float valve. The problem with that is:
1. When is pH the highest? When the lights are on.
2. When does most of your daily evaporation occur? When the lights and fans are on.
3. When is pH the lowest? When the lights are off, near the end of the “lights off” time.
With my float valve set-up I was adding most of my (high pH) kalk based top-off water during the day, when my pH was already peaking out. And not adding any of that (high pH) kalk water at night, when the tank is at it’s lowest pH, and really needed it.

My tank evaporates 1 - 1 1/2 gallons per day. I set my dosing pump to dose 1 gallon of kalk from the minute the lights go out until they turn back on (14 hours). That puts the high pH kalk into the tank at the very time of day when I need the pH rise from it the most. It has brought my daily lows up significantly and has worked very well for me.

Hope this helps.

 

[Randy Holmes-Farley]

Most combustion gases from a furnace or hot water heater better be going up the flue, or else you are at substantial risk for carbon monoxide poisoning.

Gas stove, that's another story, and is a big source of CO2. So are people and pets.

 

[tsr770]

I'm doing the airstone in a gallon of tank water on the front porch as I type this.. gunna go out to dinner and see what happens.

One thing that I have noticed is the since upgrading my skimmer to the meshwheeled MSX from a AquaC EV120 it has dropped from 7.75-7.8 to 7.65. I am guessing that the new skimmer is putting way more air into the water than the old one. Also picked up some tubing to run outside thru the frame of one of the basement windows.

Would putting glass tops over most of the sump have any effect on the CO getting to the tank?


And yes Randy, we have a carbon monoxide meter/alarm in the basement.

 

[Randy Holmes-Farley]

A gallon may take too long, so try a cup if you notice no difference. CO2 is slow to equilibrate.

Yes, if there is excess CO2 in the air, a bigger skimmer can drive down pH more.

Would putting glass tops over most of the sump have any effect on the CO getting to the tank?

If CO is getting to the tank, that would be bad, but very bad for you too. There should be no CO in your home.

 

[tsr770]

<a href=showthread.php?s=&postid=13560539#post13560539 target=_blank>Originally posted</a> by Randy Holmes-Farley
A gallon may take too long, so try a cup if you notice no difference. CO2 is slow to equilibrate.

Yes, if there is excess CO2 in the air, a bigger skimmer can drive down pH more.

Would putting glass tops over most of the sump have any effect on the CO getting to the tank?

If CO is getting to the tank, that would be bad, but very bad for you too. There should be no CO in your home.

Ended up using about a quart of water outside with a airstone for like 3 hours. PH went from 7.68 to 7.98 in the time it was out there, Looks like its time to get some fresh air into the tank from outside.

CO was supposed to be CO2.... I know CO is a bad thing.

Next question is.... Will storing my RO/DI water in the basement where I am possibly having CO2 issues mess with the RO water sitting in a storage tank? I try to keep like 30 gallons on hand at all times just incase.

What should normal RO/DI water have for a PH reading, I just now thought about checking mine to see what is says... maybe I will have to run down there and drop the Pinpoint probe in there and see.

Another thing that I did check down there is a friends 12 gallon nanocube that I am watching sits across the room from my sump... same top off water, same water change water, and the PH in that little tank is 8.15. Very possibly it is because it is pretty sealed and doesnt have a skimmer injecting the ambient air into the water like the big tank does.

Thanks a ton for all the help so far guys, hopefully I can get this thing straightened out.

 

[Randy Holmes-Farley]

Looks like its time to get some fresh air into the tank from outside.

If you can accomplish that, then that's likely the best method. That might be hard or expensive in February, however.


What should normal RO/DI water have for a PH reading, I just now thought about checking mine to see what is says... maybe I will have to run down there and drop the Pinpoint probe in there and see.

Don't bother. The ph of RO/DI, when made properly, is not accurately read by meter or kit, and is NEVER the cause of low tank pH.

Next question is.... Will storing my RO/DI water in the basement where I am possibly having CO2 issues mess with the RO water sitting in a storage tank? I try to keep like 30 gallons on hand at all times just incase.

Some CO2 will enter the RO water after manufacture, yes. More will enter seawater when you make it.

I discuss such issues here:

Reverse Osmosis/Deionization Systems to Purify Tap Water for Reef Aquaria
http://reefkeeping.com/issues/2005-05/rhf/index.htm


from it:

http://www.reefkeeping.com/issues/2005-05/rhf/index.php#8

Final Effluent pH

Aside from the issues discussed above concerning the effluent’s pH when the DI resin becomes depleted, the final pH coming out of an RO/DI system should not significantly concern reef aquarists. Many aquarists with low pH problems have asked, for example, if their aquarium’s low pH may be caused by their replacing evaporated water with RO/DI water that they measure to have a pH below 7. In short, the answer is no, this is not a cause of low pH nor is it something to be generally concerned about, for the following reasons:

1. The pH of totally pure water is around 7 (with the exact value depending on temperature). As carbon dioxide from the atmosphere enters the water, the pH drops into the 6’s and even into the 5’s, depending on the amount of CO2. At saturation with the level of CO2 in normal (outside) air, the pH would be about 5.66. Indoor air often has even more CO2, and the pH can drop a bit lower, into the 5’s. Consequently, the pH of highly purified water coming from an RO/DI unit is expected to be in the pH 5-7 range.

2. The pH of highly purified water is not accurately measured by test kits, or by pH meters. There are several different reasons for this, including the fact that highly purified water has very little buffering capacity, so its pH is easily changed. Even the acidity or basicity of a pH test kit’s indicator dye is enough to alter pure water’s measured pH. As for pH meters, the probes themselves do not function well in the very low ionic strength of pure freshwater, and trace impurities on them can swing the pH around quite a bit.

3. The pH of the combination of two solutions does not necessarily reflect the average (not even a weighted average) of their two pH values. The final pH of a mixture may actually not even be between the pH’s of the two solutions when combined. Consequently, adding pH 7 pure water to pH 8.2 seawater may not even result in a pH below 8.2, but rather might be higher than 8.2 (for complex reasons relating to the acidity of bicarbonate in seawater vs. freshwater).

 

[aqua1206]

Thanks for your question and the responses it's been very helpful.
I got my outside air plumed for the skimmer hopefully that works.

 

[Randy Holmes-Farley]

OK, good luck.

 

[tsr770]

Hooked mine up to a outside airsource last night before I went to bed. Haven't made it down to the basement yet, but will soon... maybe its just me but the tank looks a bit nicer today. My Lobo is actually puffed up today rather than retracted like it has been.

Thanks for the info on the RO/DI PH, obviously that is why mine tested at 9.5 on my 2 different meters

 

[Randy Holmes-Farley]

:thumbsup:

We're looking forward to seeing the numbers!

 

[tsr770]

So after checking, calibrating for the 2nd time in 3 days and rechecking. The tank is bouncing at 7.99-8.00 PH. Acheived just by poking a piece of 3/8" tubing out a cracked basement window and attaching it to the skimmers air inlet silencer. About 18 hours of outside air being injected into the skimmer. Hopefully with time it will creep up a little more even, although I can live with a steady 8.0.

Over the weekend I am going to make it a little more permanent, probably drill a hole thru the wooden window frame to poke it out of and attach the 3/8" hose directly to the skimmers pump and bypass the silencer.

Now to figure out how to winterize the inlet hose so it doesnt get clogged with snow or any of that other fun stuff we get here.

 

[rick s]

I'm glad it's working for you Josh. :thumbsup:

I have one thing for you to remember:
Anything that gets near that outside hose inlet is a direct link to your tank. If you put down fertilizer, spray weed killer or bug killer, or if the county pest control comes around and sprays for mosquitos, etc, that hose is going to bring the pesticide right into your skimmer. So, just remember to disconnect it for that day, or so.

 

[tsr770]

<a href=showthread.php?s=&postid=13567769#post13567769 target=_blank>Originally posted</a> by rick s
I'm glad it's working for you Josh. :thumbsup:

I have one thing for you to remember:
Anything that gets near that outside hose inlet is a direct link to your tank. If you put down fertilizer, spray weed killer or bug killer, or if the county pest control comes around and sprays for mosquitos, etc, that hose is going to bring the pesticide right into your skimmer. So, just remember to disconnect it for that day, or so.

Well no neighborhood bug sprayers here, although where I plan on putting it outside is next to a flower bed, so I will have to keep an eye on it there. Although there should be nothing but snow to worry about untill next April or so. I am thinking that I may run 1/2" PVC across the basement and out under the deck so that I can almost guarantee no outside chemicals get in there. Plus I am also thinking about trying a air pump in a sealed box hooked up to the PVC too and run a airstone in the sump also.

After 12 hours of lights out the PH is down to 7.92. I have a refugium in the sump with a 10" ball of cheato in it on a reverse light cycle... Any other macroalgae resperate oxygen better than the cheato does? I am guessing the more leafy stuff does better?

You guys have been a TON of help, and I plan on using this thread to help me keep tabs on my PH levels as time goes on so that I dont forget about them

 

[HighlandReefer]

Putting your air pump in a box sounds like a good idea to protect it from moisture, plus you can rig up a carbon filter on the air intake to the box to add additional protection. Pesticides are removed by carbon filtration and it would not take a lot to mess up your tank. Cartridge filters for respirators are sold to protect from pesticides and other materials, which are not very expensive & I believe they can be rigged up fairly easily. Make sure you plug the air pump into a GFCI outlet to prevent electrocution from the moisture.

 

[Percula9]

Try 24 hour cycle on the refugium.

 

[tsr770]

<a href=showthread.php?s=&postid=13570750#post13570750 target=_blank>Originally posted</a> by HighlandReefer
Putting your air pump in a box sounds like a good idea to protect it from moisture, plus you can rig up a carbon filter on the air intake to the box to add additional protection. Pesticides are removed by carbon filtration and it would not take a lot to mess up your tank. Cartidge filters for respirators are sold to protect from pesticides and other materials, which are not very expensive & I believe they can be rigged up fairly easily. Make sure you plug the air pump into a GFCI outlet to prevent from the mositure.

The cartridge idea is great I will for sure use that.

Rather than keeping the pump outside where it is subjected to the weather I was thinking a run of PVC tube sticking out of the house and then attached to a acrylic box in the basement where the pump would be housed, also on the box I could put a nipple to attach my skimmers air intake tubing. Kinda two birds with one stone...