pH issue - need some help please

[02tts]

So I have a wet/dry system from lifereef and a skimmer from him as well on a 265G tank, that being said, I'm having an issue maintaining an acceptable pH level....I can not for the life of me keep it about 8.15 from 6-1am and 8.11 the rest of the time (lights come on at 4pm), tank temp is ketp at 79 with a chiller. Here are rest of water values:

Ammonia: 0
Nitrites: 0
Nitrates: 20
Salinity: 1.022
Calcium: 417
ORP: ~340 (no ozone used)
Alkalinity: 3meq/l (8.4 dKH) [have tried up to 4meq/l or 14dKH]
pH: 8.11 - 8.15 ( I would really like to achieve 8.25 to 8.3) (as you can see, the swing is not that big, and would not be noticeable on a chemical test kit, but I can not get passed 8.16, 8.17 no matter what I do).

Things done to test to see if anything might be causing it:

1. removed all sand, and all live rock,tank is empty with just fish - only 10 small fish - same thing, no change
2. cleaned out all filters and skimmer - nothing since everything was already cleaned
3. remove glass canopy's in case too much CO2 was getting trapped in the tank - no change, which means I don't have a CO2 problem
4. added two 4" airstones to the sump - went up by .02 (I have a two different types of digital readers)
5. tried new CaribSea Aragamaz Select Dry Sand which - no change

Products Tried to bring pH up:

1. Natureef Seal Alk
2. Kent Marine pH buffer
3. Seachem Marine Buffer (blue label)
4. Seachem Marine Buffer (purple label)

Even more simple test to determin cause:

1. took tank water and let it sit outside of tank for up to 8 hours - no change
2. took tank water and let it sit for up to 8 hours with an air stone - and pH went to 8.24 to 8.25 and stayed there!!!!

So...what does does this all mean...to me, it would sound to me, and I'm no chemist or expert on this, but that the tank is somehow low or being starved of oxygen...could this be the case...and if so, what is the solution...I don't want to have to put airstone inside the tank!

Help please, this is driving me nuts!


p.s. - would this have an affect on high nitrates...I would think so but I need some expert opinions.

[roka64]

You can raise the pH naturally by making more surface ripple.
Do you have a lid?
What time are you taking the readings? The same time every day?
I don't think pH has a huge direct effect on high nitrAtes.
Personally, that is not a bad pH reading. Remember, stability is better than the "perfect" temporary pH....

[ccCapt]

IMO, there is nothing wrong with that pH. 8.1 is fine.
Here's a few good reef chemistry articles on pH.
The "How To" Guide to Reef Aquarium Chemistry for Beginners, Part 3: pH
Low pH: Causes and Cures
High pH: Causes and Cures
I'll also add this one, since it's a recap of the above.
Solutions to pH Problems

[02tts]

So to answer some questions:

1. As for pH readings and times, yes, pH readings are looked at the same times since it's being reported by an Aqucontroller, so it's being reported on the hour.

2. I do not have the lids on the tank now, and I have tried rippling the water substantially with a little sucess, BUT, the evaporation rate of the water is out of control and it border line rains in my house

3. Also, the question regarding the high nitrates was actually surrounding the low rading of pH do to what I think is causing it, low oxygen in the water...would this increate or decrease nitrates...???

4. Yes, 8.1 is fine, but I really prefer 8.2 to 8.3, and so do some of my tangs and angels, moreso the tangs than anythying, while the others really don't seem to care/mind.

[roka64]

265 G is a big tank, you will need lots of surface ripple to increase the pH. How much flow do you have?

[02tts]

flow is not a problem, I have a 3 week old reeflo wahoo, which I've had to valve down.

[lance]

Is that pump a powerhead or a return pump.

Water flow will effect your PH as with the time of the day you test and your tanks age.

You want around 5300 GPH flowing in your 265 gallon from independent sources.

[Kurt_Nelson]

Have you calibrated your pH meter?

Don't forget to take into account the accuracy of the pH meters that we use. The amount of error possible with a "perfect" meter - calibrated or not - is more than the amount you're trying to adjust for! So you could just be chasing ghosts.

I don't think your fish or corals really care if it's 8.15 or 8.25... as long as its consistent.

[02tts]

it's the return, can't do more than that on a pre-drilled glass tank, and not going to drill tank after the fact. Also on a fish only tank or even a reef tank, I'd have to say while more is always better as is naturally ocurring in the ocean, I'd have to say that's overkill in my opinion.

On mine I'm limited by 1" drains of ~600gph drain capacity per.

[lance]

You need powerheads for creating a water current throught the whole tank. The drain and return are just 1 part of your eco system. Then water movement would be another part.

[lance]

Then the fact the airstones helps is another indicater. THe bubbles produced from them isnt the type of oxygen you water needs. Salt water receives its O2 source from a gas exchange at the surface creat from water movement.

Then if you have good flow the LR and LS will convert ammonia and nitrate into nitrogen which will be released at the surface. Removeing the glass top was one of the best things you could have done . Now you need a few powerheads for water movement. This is not my opinion but a fact that should be learned before any water is added to the tank.

[02tts]

kurt while I realize that's possible it's not something that's happening here, I'll tell you why:

1. Yes they are calibrated and only 2 months old
2. In mFathets tank I setup for him both are consistent with a reading of 8.28 to 8.30
3. When I make water it reads 8.34 to 8.40 - I've used tropic marin which many pros sweat by and Red Sea, which is my favorite

So they're taking accurate reading, specially when x-referenced with Nutrafin chemical testers.

Also, I belive this would be a two fold solution. Meaning if I can manage to get more O2 into the water not only would the pH go up and stay up but nitrates would prob be lower do to more effective nitrogen cycle, without me needing to use nitrate sponges ....

[02tts]

Lance - been doing this a long time... And while I do appreciate all help I do have 2 korolia 4 pumps, which I thought I had indicated, regardless, water movement inside us no problem as the korolias do a fine job at moving water throughout the entire tank.....

Hence why this is driving me nuts... Yes if I really agitate the surface it goes up, but at what cost 5-6 gallons per day of evaporation!

That's crazy!

[lance]

You stated you have a 265 gallon. Is this right? If so then this isnt near enough. You want a constant 5300 GPH. 2 K-4's and a 600 GPH return you only half way there.

[roka64]

"Yes if I really agitate the surface it goes up, but at what cost 5-6 gallons per day of evaporation!"

As stated earlier, this is the solution. If you don't want to top off that much a day either move your lights higher or stick with a decent, consistant "lower than you like" pH. I hope that didn't sound mean or come off the wrong way. Have you thought of an auto top off system?
I just thought of two more options.
Get the deeper water to better exchange with the surface (thus the additional flow), remember the O2 exchange happens at the surface.
2nd option, lower your salinity.
How deep do you have your pH probe?

[02tts]

pH probes are at top and half way, have also taken readings from sump, and from all diff. locations in tank - all same readings, with the exception of the sump varying by .01.

going to replace the koralia 4 that I have for the two upcoming Korolia 6's, that along with the (2) returns will provide 5600 GPH..but I'm afraid this may be too much flow for some fish, will see, I usually try to set the flow on a 45 degree angel from the top so as to stir the water on the bottom to come up..we'll see what happens, if not, I'll just have to live with the 8.1, which should be safe for everything, just not as comfortable for some.

also, more importantly though, how will this affect my nitrates...do to lower oxygen in the water....?

[02tts]

here is another observation..i take it back about the ripple on the water...I just pointed both of my returns to create a large riple on the water since last night, and the pH actually dropped...it's now at 8.05...so it actually dropped by .05, while that is normally the case at night, it should of started to pick up by now....lights turn on at 4pm until midnight, so they're on 8 hours a day....

any other thoughts...?

I've had 90, 125 and 150's before with no issues, this 265 is just cracking me...

(keep in mind when making water, it's at 8.4 and I change 20% to 30% every two weeks), but the pH drops to 8.1 within hours...

I want to try and isolate the issue and try to restore pH to normal levels without having to dose anything...alkalinity is at 3meq/l right now and calcium is at 400.

[cmor1701d]

How long after making a new batch of sw are you testing the pH?
As others have stated 8.1 is perfectly acceptable.

[SpeedEuphoria]

I think you need to take the water and let it sit out for 24hrs and test PH.

Also do the same w/ an air stone for 24hrs and test PH.

[02tts]

within 3 hours is gradually declines to 8.10

as for testing the water out, etc...yes, that test has already been as denotes on the notes.

water outside or inside the house measures the same with or without an airstone, key is that if I do use an airsone, it climbs to 8.25 to 8.27 without an issue and stays there...

I have (2) koralia magnun 6 coming tomorrow, while they'll move more than plenty of water including the 1200GPH from the returns, I highly doubt this will have any impact on pH, I hope it does, but given test results thus far with (2) koralia 4's and the returns, I highly doubt to magnin 6's will drastically increase pH by that much if any at all, but we'll see, I'll post results several hours after I put those in tomorrow to see if they made any sort of difference.

and rippling the water has not done anything yet, I'm agressively agitating the water on top since 7am, enough where it's caused a moderate level of evaporation thus far with zero effect on pH....