need help with ph

[SALTWATERSIG]

lately i've been plagued with having to dose limewater into my sump at a rate of 2 gallons per day during lights off period. by doing so my ph stays at roughly 7.85 and then when lights are on the ph climbs to 7.99-8.00. if i don't dose the lime water ph at night drops into 7.6-7.7 keeps dropping. my parameters are as follows

salinity 1.26
calcium 480
mag 1300
alk 10.8-11.2
phos undetectible
nitrates 0-.5
temp 78-80'

photo period is t5 actinics for 9 hours and metal halides for 7 hours (halides on with t5s) . i have a calcium reactor that effluent ph is 6.75

i'm wondering what i can do to be able to leave for a weekend or short vacation......i am looking at adding a top off unit with kalk reactor and dosing pump. is there anything else to play with to try to get my ph up into the 8.1-8.3 ranges without making alk go higher?

also running mostly sps with some lps and appx 8 fish .

[SALTWATERSIG]

sorry ....salinity should be 1.026

[tunaluver]

odd.. im having exactly the same problem.. i was kinda having problems before and it was atleast sticking at the 8.0 area over night then one night i actually watched the ph drop on my monitor and now it only gets up to about 8.0 at its highest and 7.6 or less at night. im tagging along here

[Percula9]

Do the bubble test to see if room CO2 is the problem. Add a refugium to help absorb CO2. Are you running a calcium reactor?

[SALTWATERSIG]

yeah i have a refugium stocked with chaeto and also running skimmer and phos reactor. i have some rubble rock in there also.

[SALTWATERSIG]

was'nt sure if you were asking me but ...yes i have a calcium reactor as well.

[Billybeau1]

When is the last time you calibrated and cleaned your pH probe ?

[SALTWATERSIG]

probe is about 6 months old and i calibrated it this past monday.
not sure what you meant by cleaning other than just rinse off in ro/di water between calibration packages.

[Billybeau1]

You'll want to soak it in either vinegar or hydrochloric acid for an hour or so. Then brush it gently with a soft bristle tooth brush.

Then calibrate it with 7 and 10

I do mine once every 2 months or so.

[bertoni]

I'd try the aeration test described in this article:

http://reefkeeping.com/issues/2004-09/rhf/index.htm

Also, this article describes an easy sanity test for pH meters:

http://web.archive.org/web/200210150...io/default.asp

[Percula9]

Low Ph is one of the problems associated with calcium reactors. Try dialing back the reactor or alternate with your reactor and the kalkwasser drip. I think you will get a better control on the PH. Remember you are deliberately injecting CO2 into the reactor to lower its PH to cause the dissolution of calcium carbonate. Try 24hr light cycle on the refugium.

[SALTWATERSIG]

i will clean probe with vinegar tonight and see if that makes any change in ph monitor readings. i thought the ideal ph coming from cal reactor effluent was between 6.5-6.9? mine varies a little but for the most part 6.7 i could increase my effluent flow but my thought was with more effluent coming out than at a slower drip i would again be battling with ph in tank getting lower quicker. by the way i have been running refugium light 24/7 for appx last 2 months.

[MarkGP]

Add an effluent chamber to your calcium reactor to help dissipate the co2 before it goes into your tank and lowers the pH. You could also put the co2 solenoid on a timer, since it sounds like you don't have a controller, to shut off the co2 flow when your lights go out then have it start up again before your lights come back on.

[SALTWATERSIG]

ok.....i cleaned and recalbrated my ph probe and now my reading is 8.12 .....and i roughly have about 2 1/2 hours lft of halide photo period followed by an additional 1 hour of t5 actinics , then at that point i dose again. so it seems i need to do a little more probe cleaning in the future...thanks billybeau1.
i do have a two cylinder ca reactor mrc brand and the effluent reading i take is from the 1rst chamber.....what are the advantages to putting co2 solenoid on a timer so that its is not on during lights off period which would be about a 15 hour stretch?

[Billybeau1]

On the probe.

I have zero calcium reactor experience. JD's real good at this. Let me see if I can find him.

[jdieck]

Originally posted by SALTWATERSIG
ok.....i cleaned and recalbrated my ph probe and now my reading is 8.12 .....and i roughly have about 2 1/2 hours lft of halide photo period followed by an additional 1 hour of t5 actinics , then at that point i dose again. so it seems i need to do a little more probe cleaning in the future...thanks billybeau1.
i do have a two cylinder ca reactor mrc brand and the effluent reading i take is from the 1rst chamber.....what are the advantages to putting co2 solenoid on a timer so that its is not on during lights off period which would be about a 15 hour stretch?

I hope you recalibrated the probe after cleaning it.

The calicum reactor will tend to lower the PH of your tank but a drop of more than 0.1 may indicate improper setting or a reactor that it is too small for the tank consumption although capacity does not seem to be a problem in your case as you are able to maintain alkalinity with an effluent at 6.75 PH
If it is really the reactor and not the air around the house there are a couple of tricks that can help here.

a) Drip the effluent of the reactor at the inlet of the skimmer. That will help disipate any potential CO2 gas in the effluent and will accelerate the conversion of carbonic acid to bicarbonate and the bicarbonate to carbonate. Insure that the effluent line is not submerged in the tank water but it drips.

b) If posible hose fresh air from the outside into the skimmer. If you have an enclosed fish room or stand, try increasing ventilation.
Install some air vents on the stand.

c) If your effluent rate is relatively high (>50 ml/minute) and your effluent PH is high also (>than 6.6) it is better to adjust the reactor for a lower effluent and lower PH.
Eventhough you will have lower PH in the effluent the longer retention time of the water inside the reactor helps improve the utilization of CO2 and allow for higher saturation of the effluent as it will give time for the carbonic acid to bicarbonate ratio to stabilize before leaving the reactor.

c) If you are using large sized media in the second chamber, replace it with small sized ARM aragonite which will have more exposed area and dissolves at higher PH thus making your second chamber more effective. That second chamber should increase the effluent PH by about 0.05

d) The trick on the timer works also but it is a bit of a pain to set as you need to adjust the reactor to provide al the alkalinity within the 8 to 10 hours of lighting, this may imply higher effluent at lower PH which may increase the impact so you need to tray to see if it works well with your operating conditions.
My preference is to run the reactor continuously and drip Kalk at night.

[SALTWATERSIG]

thanks for the info jd ...i will first route my effluent drip line to the inlet area of skimmer.....i thought i read on mrc equipment set up
procedures that the effluent line should not be placed before the skimmer. where should the ph probe be placed ? i had it placed before the skimmer in the area where tank returns are at but if i'm putting effluent drip line in that area now should i place it maybe it section of sump where return pump is at?(after regium area)

[SALTWATERSIG]

if anyone cares....i recieved my lamotte alk test kit today and i got a 8.3 dkh ....also tested with my now old news salfert kit and it reads 10.6 dkh.

[jdieck]

Originally posted by SALTWATERSIG
thanks for the info jd ...i will first route my effluent drip line to the inlet area of skimmer.....i thought i read on mrc equipment set up
procedures that the effluent line should not be placed before the skimmer. where should the ph probe be placed ? i had it placed before the skimmer in the area where tank returns are at but if i'm putting effluent drip line in that area now should i place it maybe it section of sump where return pump is at?(after regium area)

Nope, nothing on the instructions I can find mentions the effluent line and skimmer. In general the agitation and air contact of the effluent and water mix in the reactor will speed up the process of CO2 stripping.
In any case yes drip the effluent in the inlet of the skimmer. TO be able to measure the effluent PH you may want to set up a small plastic cup in a way that the effluent drips into the cup and the cup overflows into the sump. To measure the effluent PH just dip the probe in the cup.
If you have a two chamber reactor, measuring the efffluent PH for control will not be my preferred choice as it will be higher and specifically it takes too long for the Pout of the second chamber to change when making changes to the CO2 input.
For a two chamber reactor measuring the PH in the first chamber is the way to go. You may need to set up a PH probe sump to do so.

To measure the system tank PH the probe at the main tank will be ideal, the next best location would be the return pump chamber in teh sump away from reactor effluent or kalk drip.