skimmer with outside air hose ?Hi

[jolt]

Must say that running a hose outside, or even using a CO2 scrubber, made very little difference to my tank's pH. I'd argue that if either of these approaches do make a material difference, gas exchange in your tank maybe poor.

In my case it is simply that my house has too high CO2 level due to its being very sealed up. Confirmed with Aeration Test as prescribed by Randy here:

Low pH: Causes and Cures by Randy Holmes-Farley - Reefkeeping.com

If low PH is due to a different cause then it is assumed this approach won't work.

 

[ca1ore]

Understood. All I'm saying is that if your display is sitting in a high CO2 environment, and is well circulated, lots of CO2 is dissolving into your tank through the waters surface. So unless you put a good cover over the tank it doesn't really make sane to me that a fresh air skimmer line would make much difference at all. And that has been my own observational experience.

 

[jolt]

I know many have debated and there are folks on both sides of the fence (as evidenced for example in this thread). For me, it raised my Ph measurably in 10 days. From 7.8-7.9 for 4 months running to consistently 8.05-8.1 I'm very happy I did it.

 

[zforce]

Just think about the gas to water exchange happening inside the skimmer. Then, would you want introduce fresh air, or air that has higher CO2, lower O2. I have tried both, outside line made a huge difference, as I have a tight house and lots of breathers..... It took about a week on my 300 gal system to fully come to equilibrium. PH bumped 0.3 units. I have BRS unit with carbon in line as described previously, running a downdraft skimmer that pulls a ton of air. The amount of air your skimmer pulls will be relative to the max length of tubing required to get outside.

 

[mcarroll]

In my case it is simply that my house has too high CO2 level due to its being very sealed up. Confirmed with Aeration Test as prescribed by Randy here:

Low pH: Causes and Cures by Randy Holmes-Farley - Reefkeeping.com

Key quote from the article for anyone else planning to chase a pH number:

[...]many reef aquaria operate quite effectively in the pH 7.8 to 8.0 range[...]

There are details that I've omitted with the "..." because they distract from the point.

Unless you are just looking for something to do, raising pH like this is not likely to produce a noticeable benefit but will definitely add cost and complexity...you'll be fine without doing it in 99% of cases. My SPS system has been in this range for something like 8 years.

My advice is to not mess with pH unless someone in your tank tells you to. Know what I mean? (If you pH is below this range, probably a different story...but never personally seen that happen.)

 

[Alabamareef]

Must say that running a hose outside, or even using a CO2 scrubber, made very little difference to my tank's pH. I'd argue that if either of these approaches do make a material difference, gas exchange in your tank maybe poor.

It's not the gas exchange inside the tank, it's the ambiant air that can cause an elevated C02 which can affect the pH. For example if you live in a cold area and your home is always closed up this can elevate the C02 which can affect the pH. This can be cured by opening a window a few minutes a day. In my case the C02 scrubber is doing great. For others it may be an outside line of fresh air and others never have this issue.

 

[ca1ore]

It's not the gas exchange inside the tank, it's the ambiant air that can cause an elevated C02 which can affect the pH. For example if you live in a cold area and your home is always closed up this can elevate the C02 which can affect the pH. This can be cured by opening a window a few minutes a day. In my case the C02 scrubber is doing great. For others it may be an outside line of fresh air and others never have this issue.

No, you missed my point (or I didn't make it very well ). If you have a well-circulated tank open to your room's ambient environment, and that environment is high in CO2, its going to be absorbed through he water surface and affect pH. And if the tank is well circulated that absorption will just be more efficient; and chances are you are also at or close to O2 saturation. Running the airline outside will then make very little difference to the pH. If it does, I'd argue its because the tank is not also able to absorb CO2 from your room, which in turn means gas exchange is poor. That was my point. Maybe folks disagree, but it makes sense to me given my own observations.

 

[Alabamareef]

The CO2 SCRUBBER does not remove carbon dioxide from the aquarium. It prevents excess CO2 from accumulating in the tank water. Low levels of CO2 are always present in the aquarium. Yes good turnover in a reef tank is a must for gas exchange. As far as C02 being absorbed by your tank I think the C02 is brought into your tank via the skimmer. This is why an airline outside air line or a C02 scrubber or open window helps.

 

[vladandlilith]

I tried running an airline outside, but that did not have a noticable effect. Then I made a DIY CO2 scrubber out of a Gatorade bottle and got a bag of soda lime from a friend of mine who is a veternerian and now my pH stays between 8 and 8.1 instead of 7.8. All I did was take a Gatorade bottle (the size sold at convience stores) and drill 1/8 inch holes all around the bottom then drill a 1/4 inch hole in the top. I siliconed the airline into the top then filled the bottle about 3/4 of the way up. Once I hooked it up to my skimmer, it was like night and day. I know BRS sells the soda lime, but I found a medical supply company that sells 3lb bags (I think) for 7.99. The exact same bag that my friend gave me.

 

[Alabamareef]

I tried running an airline outside, but that did not have a noticable effect. Then I made a DIY CO2 scrubber out of a Gatorade bottle and got a bag of soda lime from a friend of mine who is a veternerian and now my pH stays between 8 and 8.1 instead of 7.8. All I did was take a Gatorade bottle (the size sold at convience stores) and drill 1/8 inch holes all around the bottom then drill a 1/4 inch hole in the top. I siliconed the airline into the top then filled the bottle about 3/4 of the way up. Once I hooked it up to my skimmer, it was like night and day. I know BRS sells the soda lime, but I found a medical supply company that sells 3lb bags (I think) for 7.99. The exact same bag that my friend gave me.

Can you post a link where to buy it

 

[hart24601]

When I ran my airline outside with a scrubber I noticed a nice jump in pH, but it still wasn't very high. So I have now starting dosing kalk at night. I dose 2 part, and still do, but I reduced the dose and did the calculations so the tank gets the same amount of Ca and Alk per day.

I do not run it in my top off, I don't like the variability. Since my GF got me an apex all I had to do was buy the BRS 50ml/min doser and set it up on the apex to dose at night every hour. I only dose about 1500ml right now over the night, the 2 part does the rest, but the impact on pH is huge on my 120 to keep it from dropping much at night. My tank evaps 1-2 gallons a day, so the 1,500ml is hardly anything and I still use my ATO with RO/DI for evaporation. I don't ever plan on the majority of my dosing to be kalk, but wow it's great for pH issues.

If you want to raise pH I would suggest either a reservoir of kalk or using a kalk stirrer. You can still use 2part or a reactor for the bulk of the dosing and just do kalk as a bonus and pH stability at night.

 

[Alabamareef]

if your Alk is good it will show by having a good pH. If my pH starts to drop and it's not my co2 scrubber needing the media changed that's a good indication my Alk or kalk is out of balance. A good stable pH shows your system is healthy.

 

[tgp4274]

ok so my house isn't exactly perfect...... my alk is at 8 and I just checked my ph with a meter (just cal'd before checked) n my ph is at 7.7

 

[hart24601]

The relationship between alk and pH is in Randy's great article here:

Chemistry And The Aquarium: The Relationship Between Alkalinity And pH ? Advanced Aquarist | Aquarist Magazine and Blog

Keeping alk a good levels (which people seem to run lower now, especially with carbon dosing) will not ensure the pH you want even with running an ouside line in all cases. The outside line helps a bit, but the tank still absorbs lots of CO2 from your house doing it especially if you have an uncovered tank with lots of surface agitation. Looking at Randy's article in the perfect situation an alk of 8.5 would have a pH of over 8.3. Limewater uses the CO2 in the water to form calcium carbonate so it reduces CO2 levels in the tank really well. That can be a problem if you are trying to dose all your Ca and alk needs and it drives the pH too high, but IMO it's perfect for night time additions where the pH naturally falls due to lack of photosynthesis.

I hope Randy will correct me if that isn't right.

Here are some of my graphs. Before the outside line pH would get to 7.8 at night, sometimes lower. After adding the outside line it bumped it up to right around or a bit below 7.9. Adding the co2 scrubber didn't have as large of an effect for me, but it still helped a bit. Dosing on a little bit of kalk for my tank (1400ml or 0.3dkh) broken into groups every hours has resulted in night pH staying around 8. The tank has quite a bit more demand for that, so I can bump that up if I want, but a low of 8 is pretty good. If I knew how easy kalk was to setup and dose I wouldn't have bothered with the outside line.