PH Crashing

[mcm13yn]

25 gal. monthly water changes
Salinity: 1.027
Temp: 76
alk: 1.5 meq
calcium: 500 +
135 gal display
50 gal sump
100+ lbs LR
T5 54w x 4 (on 12p.m.-12a.m.)
HQI 250W x 2 (on 3p.m.-8p.m.)
5 fish
2 clams
2 open brains
zoas
Tank Established Dec 2009

My PH range has always been 7.9-8.2 and it's dropped to 7.6-8.0. What seemed to kick it off was a HQI on time increase of 2hrs to see if my PH range would rise. I want my PH in the range of 8.1-8.4 because I've experienced this range promotes new growth with corals. Another mind bender is I've added Baking Soda (bicarbonate) and upon its introduction to the system it brings the PH down a .8 or more. I know the alk is low and calc is high, but what gives? If anyone can offer some help it would be appreciated. james

[hobogato]

the pH is low because your alkalinity is low. first, make sure your test kit for pH, alkalinity, and calcium (as well as magnesium) are not off by having someone else test for those things or testing again yourself with a different test kit. in order for baking soda to raise pH, you must bake it first. here (http://www.reefcentral.com/forums/showthread.php?t=1739333) is a good quick discussion on rc about baked vs. regular baking soda

until you get your alkalinity up, you will continue to have pH swings. i would bet your magnesium is also low and that is making it difficult to get your alkalinity where you want it.

[hobogato]

what salt are you using btw?

[mcm13yn]

Oceanic - so what do u do to get the alk up?

[alton]

Your calcium shows 500+ does this mean 600/700? If so this is why your Alk is so low, you need to use something like instant ocean (low calcium) to get your calcium down and Alk up. Richard at CB pets and Ken at Aquarium Sales and Service used to say your aquarium is like a bowl of marbles, if you have too much of one then it will knock out some of the other because you can only have so many marbles in the bowl. Most Calcium kits are inaccurate after 500 so take half aquarium water and half DI to do your test and multiply x 2.

[BSJF]

Be careful when raising your alk when your calc is high like this or you will just get a snow storm in your tank. I would recommend using water changes to correct the situation rather than dosing alk. Alton is right, the best salt to use in this case is IO. Definitely don't use Oceanic or any other Pro type of salt right now.

You can use the Salifert test, just fill a second syringe and keep going until it turns color, then add the total of the two together to get what your real calc is. But it doesn't really matter too much at this point, because you are out of balance regardless of how high it is.

Also test your magnesium, because if you are out of balance it could be the cause. And, IO is typically low on mag.

[hobogato]

oceanic is notorious for driving calcium up at the expense of alkalinity. i have heard of lots of people using half oceanic and half instant ocean to get better levels from their makeup water. there are many other salts that will may work better for you, i like reef crystals. you can start doing water changes with a different salt, you can use baking soda as described in the reefcentral thread i linked above, or you can use a buffer additive. what ever you do, dont do it too fast and make sure that your calcium is dropping at the same time. if you run out of room in the bowl of marbles (from alton's post), then the calcium will precipitate out and you will have a snowstorm in your tank. be sure to test magnesium as well. low magnesium will affect your ability to get the alkalinity and calcium as high and stable as you want it.

edit: dang it, lorraine beat me to it :)

[mcm13yn]

Ok, I put in 1.5 cups of baking soda on Friday - PH range 8.0-8.2 - CA 400 - KH 14 - no snow - no msg kit. Low PH has been a problem for me since day 1. I didn't know it at the time, but the first few years I was strugling with overfeeding and flat worm/Asterina infestation. This year I belive I've the overfeeding problem undercontrol and the flat worm/asterina are undercontrol. A few months ago my PH range jumped from 7.9-8.2 to 8.1-8.4 and my tank started spurting new growth of corals, zoas were opening for the first time! - it was beautiful, but after a few weeks it went back to 7.9-8.2 and I have no clue why. I've tried different salts and don't see a change in my PH. Im wondering if my LR is leaching acid? I'm pretty sure all my LR is coral skeleton...just don't know.

[Scutterborn]

Pics of the rock?

[mcm13yn]

KH=14 CA=465 PH rang is 8.0. Ph is slowly but steadly droping...what gives???? Here are pics of my LR. 1550115502

[Scutterborn]

What is that directly under the hippo and yellow tang? Are you running your sump on a reverse light cycle? What is in the sump? I.e. macro, LR, DSB?

[hobogato]

did you check for CO2 buildup? take a cup of tank water and test the pH. then take that cup of water outside of your house and aerate it with and air stone for about 30 minutes. if the pH rises, it means you have a buildup of CO2. this could be tank specific or in your house in general if you are not letting enough fresh air in.

[mcm13yn]

that's my derasa clam - sump lights on 24hrs - LR and macro, but the macro doesnt thrive...I think it also wants a higher Ph range - no issues with CO2/enviornment air, but there are always bubbles..small ones coming from my LR? - Ph range maintains at 8.