ph on the low side

[regalangelfish]

as tested with apex probe ph in tank reads 7.6 lights off - 7.9 lights on. here are my params:
Cal 440
KH - 9
No3 - 20 ppt
Po4 - .12
mag - 1600

I get plenty of fresh air with fan in window. what could be causing this low ph condition? is this considered low? I used to see ph at 8.3 and not sure whats causing this in my tank??? please advise. Thanks

[bnumair]

cause of low pH is co2 build up. my first guess would be u need to recalibrate the pH probe as they shift/drift off. most manufacturer recommend calibrating them once a month.
i am quite sure this will solve the problem. if for some reason it doesnt then u can always install fan blowing over the sump or tank,place macro algae in sump and a refugium light on opposite hours as tanks, or co2 scrubber etc.

[Randy Holmes-Farley]

This has more:

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

[Crusinjimbo]

Try a fresh air feed to your skimmer if you tank is near access to outdoor air. Worked for me and ph stays at 8.1-8.3. Drilled a 3/8" hole in the wall for an airline feed. I have since moved the air feed to an air pump driving an up-flow algae scrubber in the sump. Results are the same. Cheap ph stability fix.

[downbeach]

If you're getting good gas exchange, i.e. skimmer, surface agitation, etc., then I'd be suspicious of your probe/calibration. I'd recalibrate and reassess. If you find your readings drifting, it may be time for a new probe.

[tmz]

I think you meant NO3 20ppm: not ppt.

[regalangelfish]

Thank you everyone for commenting... being in the hobby for about 16 years now I have been through enough Cal/alk and other chemistry swings to know that sometimes its best to take a wait and see attitude.

Randy, thank you for posting your link to PH issues as it was a great reminder. I think I have read that paper countless times over the years but its been a while that I had to deal with PH issues. My PH rarely became a problem.

So, I took the first advice here and recalibrated my fairly new probe (2.5 mo). Observation: ph reading before cal = 7.93 and after cal = 8.03 both readings are with lights on for a couple of hours. so I will check later today after a full day cycle to see where my PH is after a full day of lights on. However, I am used to seeing PH at 8.2-8.3 lights on. I am considering implementing limewater as a way to get PH slightly higher if recalibrating does not get me to where I want to be. The limewater will be supplimentation only to my Cal reactor and wont handle all of the water top off. so I may have it set just to come on when low PH occures (at night) and only for a set amount of time... I'm thinking the two little fishies kalk reactor might work well for this http://www.thatpetplace.com/two-little-fishies-kw-reactor-300?gdftrk=gdfV2226_a_7c268_a_7c6967_a_7c252671&ne_ppc_id=1463&ne_key_id=26455359&gclid=CMGwqZqQvb0CFRQS7Aod_kwArQ

I do have a small computer style fan over my sump which blows air across the top of the skimmer inlet. When that comes on so does the tank fans and the window fan which blows fresh air in. I may however try and run a 1/2" air line directly from the outside or do the cup test on Randy's PH link.

The main change with my tank is that I'm trying to convert over to predominantly LPS/SPS tank. In doing so I have been cleaning the tank up over the last 6 months or so. More and regular water changes 30% every month and siphoning the sand 2" bed every three months. Regular cleaning of the sump floor and changing out GFO and carbon once a month. I also implemented more macro into refugium, implemented bio pellet reactor and growing about 25 mangroves successfully.

I probably should have mentioned before... my tank is 105 gal display shallow reef (18" x 36" x 36") rimless w/ 36 gal sump/refugium. I run cal reactor and skimmer and led lights on refugium and main tank. I also have implemented an automatic refrigerated liquid food dispenser which feeds reef nutrition's oyster feast (2 ml) Phyto (2 ml) and a mixture of fish eggs, brine w/ spirulina, and arci pods all for the fish (4 ml). The above is dispensed daily when lights on. However, I do spot feed chunks of shrimp for acans, some LPS brains and anemones once every couple of weeks or when I remember.

so since I started cleaning and converting over I have seen moderate to good success. at first I had issues with my old MH light and converted over to LED's. I also saw high nutrient swings which have been addressed. However, I still battle trying to lower the nitrate levels but cant seem to do so... yet Its hovering at 20 ppm (thanks TMZ for the correction). my Po4 is at 1.2 -.07 using GFO. As a side note I have read that No3 and Po4 are connected? so if you wanted to lower No3 you must do so together with Po4? is this correct? I have tried taking down the GFO but I don't like what I see in the display when I do this as Po4 rose to 3.5-3.9.

Other slight issues I'm dealing with is slight hair algae on certain spots on the live rock and glass. Its really not a big issue as long as I keep up with changing GFO. I'm having a tough time growing the Chaeto in refugium. It doesn't die but I don't get great growth either..

OK I probably opened a can of worms but wanted to mention all of the above in case anyone has any suggestions for me. Thanks in advance for all of the help.

[tmz]

I noticed a loss of about .2 pH with organic carbon dosing (vokda and vinegar in my case) from 8.15 to 8.35 down to 7.9/8.0 and 8.2.I'd gues the pellets have something to do with it in our case . I got about .15 back with a CO2 scrubber. I was already dosing limewater at full saturation to approximately match top off needs from a still reservoir via peristaltic pump spread out for 24 hours for calcium and alkalinity .There was also plenty of surface agitation and bubbly skimming already in play.

f you are happy with our current alk and calcium levels ,you might want to dial back the calcium reactor to balance out the extra supplementation from the kalk if you decide to use it.

Alternatively , you could just run it the way it is . 7.9 is not worrisome ;7.6 is though. I prefer mine higher 8.2 to 8.4 or so.

[bertoni]

A low level of available phosphorus in the water column probably can reduce the effectiveness of carbon dosing (vodka, vinegar, bio-pellets, and similar approaches). That's because carbon dosing works by exporting organics via the skimmer, and these organics will contain phosphorus.

A denitrator coil or sulfur reactor can reduce nitrate without a net consumption of phosphorus, though. This article has some information on how they work:

http://www.advancedaquarist.com/2003/8/chemistry#section-12

[regalangelfish]

I observed PH raise to 8.31 at end of day yesterday and however ph reads 8.06 now with only 4 hours left to photo period. so I'm unsure what to think. but this morning I placed the newly recalibrated probe back into 7.0 and 10.0 solution and it still reads within .01-.1 accuracy so I don't think the probe will give me any more erraneouse readings...

My cal reactor is a single chamber. is there any other way to increase the efflows PH coming out of the cal reactor other than a second chamber? looks like a fully automated kalk reactor is a bigger deal on my system than I originally thought.

as for a sulfur reactor... i don't have enough expierience but from what i read last night those need to me degassed daily and knowing how I like to automate everything I don't think i would remember to do that every day. Bertoni can you tell me your expierience with those? or anyone that has first hand with these units, LMK.

[tmz]

Degassing is during the reactor cycling in process ,about the first week or so.

[regalangelfish]

Degassing is during the reactor cycling in process ,about the first week or so.

Hey thanks TMZ... can you tell me, do you think this simple reactor would be good for the sulfur media? Its s simple fluidized reactor which holds about two cups of media and I could degas using the provided ball valves. would this be enough media for my 105 gal MD and 29 gal refugium?