Low pH Help Needed

aakour · 06/26/2013, 08:54 AM

My tank pH stays low no matter what I try. Over the course of about a month and a half, I've seen it as low as 7.5 during the day and never any higher than 7.7.

My parameters from yesterday are as follows:
Ca 380ppm Red Sea/400ppm API
dKH 10.2 Red Sea/11 API
Mg 1200ppm
pH 7.7 probe/~7.6 API
SG 1.022

My tank is 46gal with ~15lb live rock, ~50lb sand/aragonite/live sand for substrate, with a ~12gal capacity sump with another ~20lb sand/aragonite. Additionally I have a 1/3hp chiller, NEXX canister filter to hold my chemical media, and all the return plumbing that total to holding about 1.5-2gal of water. So I would say there's probably at least 50gal of actual water. No Ca reactor.

For a couple weeks at the end of my Oceanic salt, my Ca was at 650ppm, and dKH at 20, while pH remained low and I did not have a Mg test. I have since switched to IO salt, and this tank has never seen anything other than water through 6 stage RODI.

I have tried bringing in outside air to the skimmer, and it made 0 difference with or without its carbon air pre-filter. My dt surface is plenty agitated, my overflow hose trickles over the water in the sump and my skimmer output does the same to create plenty of surface agitation in the first chamber of my sump.

The pH drop killed about half my mushrooms, my candy canes, half my snails-all of the turbos, and 1 of my feather dusters. My other feather duster is bigger than ever, my kenya tree is huge, my GSP are ok, and the other half of the mushrooms-while agitated-are ok. My fish, hermits, other snails, and shrimp never noticed.

Does anybody have any ideas?

t00lfan · 06/26/2013, 01:57 PM

How did the calcium and dkh get so high before, Do you dose any supps? 650 and 20 surprises me anything survived. I know someone who had it at 18dkh and lost nearly everything. I would raise the salinity slowly now that everything in your parameters seems ok.

bertoni · 06/27/2013, 01:02 AM

That SG is very low. I'd likely raise it to 1.0264 or so. I'd calibrate the device with a saltwater standard, first though. Raising the SG might help with the pH.

Other than that, the cause of low pH in an established tank always is carbon dioxide, assuming that the alkalinity is in the 7-11 dKH zone. 7.5 is low enough that I'm suspicious about the accuracy, although the low SG might explain part of that. We see a lot of problems with pH testing equipment here.

aakour · 06/28/2013, 09:11 AM

So I need to try raising my SG first. Would you recommend a higher sg mix at wc time, or top off with salt water instead of just rodi?

t00lfan, at the time, I was not supplementing anything, just doing weekly 10% wc with the Oceanic salt. I now dose IO reef builder once a week or so, and purpleup-I know purpleup is over priced, but I didn't buy it, my wife got it as a "surprise" because she's too impatient for coraline spread-2-3 times per week, as well as ~10% wc with the IO salt every weekish. My CA, dKH, and MG have been consistently in the area I posted before since switching to IO salt, even with the dosing. The entire time I was using oceanic my dKh was at least 18, typically 20+ and I never had any issues, my mushrooms and candy canes thrived at those levels in my 20g nano I had before. I do want to reiterate, when I had 600+ Ca and 20 dKH, i was NOT supplementing anything.

bertoni, When I test a new batch of salt, it typically reads at 1.025. As far as pH, I have a Milwaukee "lab" pen type probe.I have not been too suspicious of it being inacurate because my API liquid test is fairly close-and we all know those liquid tests can be difficult to interpret. I check my pH daily with the probe, and when I pull water for my weekly tests, I do the liquid test for the hell of it-I'll also do a liquid test if I think the probe is way off. When I do the liquid test, I do 3-4 tests. I throw out the first-because the first one is always way high or way low off the chart either way-then do 2-3 more and take an average of those readings-they're typically identical.

blackthunda77 · 06/28/2013, 09:53 AM

I deal with the same thing here in S. FL. The windows r closed and AC is on all day. Cracking a window open helps but not very practical with the AC loss. I am about to try a CO2 scrubber. You can make one on the cheap, just need to buy Soda Lime.

aakour · 06/28/2013, 10:14 AM

I've considered building a scrubber, just been trying anything else I can before building or adding anything else that needs consumables.

bertoni · 06/28/2013, 06:28 PM

Just add some extra salt mix to raise the SG. 1.025 is okay, though I'd go a bit higher. You can replace any evaporation with saltwater for a bit to raise the SG in the tank.

aakour · 06/29/2013, 09:48 AM

Ok, I will try that over the course of the next few weeks or so, I only have to top off about 1gal/week.

06/26/2013, 08:54 AM	#1
aakour Registered Member Join Date: May 2013 Location: Stillwater, OK Posts: 27	Low pH Help Needed My tank pH stays low no matter what I try. Over the course of about a month and a half, I've seen it as low as 7.5 during the day and never any higher than 7.7. My parameters from yesterday are as follows: Ca 380ppm Red Sea/400ppm API dKH 10.2 Red Sea/11 API Mg 1200ppm pH 7.7 probe/~7.6 API SG 1.022 My tank is 46gal with ~15lb live rock, ~50lb sand/aragonite/live sand for substrate, with a ~12gal capacity sump with another ~20lb sand/aragonite. Additionally I have a 1/3hp chiller, NEXX canister filter to hold my chemical media, and all the return plumbing that total to holding about 1.5-2gal of water. So I would say there's probably at least 50gal of actual water. No Ca reactor. For a couple weeks at the end of my Oceanic salt, my Ca was at 650ppm, and dKH at 20, while pH remained low and I did not have a Mg test. I have since switched to IO salt, and this tank has never seen anything other than water through 6 stage RODI. I have tried bringing in outside air to the skimmer, and it made 0 difference with or without its carbon air pre-filter. My dt surface is plenty agitated, my overflow hose trickles over the water in the sump and my skimmer output does the same to create plenty of surface agitation in the first chamber of my sump. The pH drop killed about half my mushrooms, my candy canes, half my snails-all of the turbos, and 1 of my feather dusters. My other feather duster is bigger than ever, my kenya tree is huge, my GSP are ok, and the other half of the mushrooms-while agitated-are ok. My fish, hermits, other snails, and shrimp never noticed. Does anybody have any ideas?

06/26/2013, 01:57 PM	#2
t00lfan Registered Member Join Date: Sep 2009 Location: Milwaukee Posts: 149	How did the calcium and dkh get so high before, Do you dose any supps? 650 and 20 surprises me anything survived. I know someone who had it at 18dkh and lost nearly everything. I would raise the salinity slowly now that everything in your parameters seems ok. __________________ Ocellaris are clowns, and so are people. Current Tank Info: 90 gal. mixed reef tank (SPS, softies, LPS,3 Clams)with 10 gallon fuge and 30 gallon sump. Lighting 2 250 MH 20k radiums with 4 t5 HO ATI(1actinic 1purple and blueplus)

06/27/2013, 01:02 AM	#3
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	That SG is very low. I'd likely raise it to 1.0264 or so. I'd calibrate the device with a saltwater standard, first though. Raising the SG might help with the pH. Other than that, the cause of low pH in an established tank always is carbon dioxide, assuming that the alkalinity is in the 7-11 dKH zone. 7.5 is low enough that I'm suspicious about the accuracy, although the low SG might explain part of that. We see a lot of problems with pH testing equipment here. __________________ Jonathan Bertoni

06/28/2013, 09:53 AM	#5
blackthunda77 Registered Member Join Date: Jan 2004 Location: East Coast/West Coast Posts: 4,887	I deal with the same thing here in S. FL. The windows r closed and AC is on all day. Cracking a window open helps but not very practical with the AC loss. I am about to try a CO2 scrubber. You can make one on the cheap, just need to buy Soda Lime. __________________ - John *blackthunda stands for a black Mistubishi 3000GT with black rims I used to own. Don't get any funny ideas! Current Tank Info: 200 Gal custom tank with dual corner overflows, 80 gal custom sump/refugium, Neptune Apex controller, Dual Lumenmax Elite reflectors with 250 Radiums, SWC 160 Cone Skimmer, 2x Jebao WP-25....and some other stuff.

06/28/2013, 06:28 PM	#7
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	Just add some extra salt mix to raise the SG. 1.025 is okay, though I'd go a bit higher. You can replace any evaporation with saltwater for a bit to raise the SG in the tank. __________________ Jonathan Bertoni

06/28/2013, 09:11 AM	#4
aakour Registered Member Join Date: May 2013 Location: Stillwater, OK Posts: 27	So I need to try raising my SG first. Would you recommend a higher sg mix at wc time, or top off with salt water instead of just rodi? t00lfan, at the time, I was not supplementing anything, just doing weekly 10% wc with the Oceanic salt. I now dose IO reef builder once a week or so, and purpleup-I know purpleup is over priced, but I didn't buy it, my wife got it as a "surprise" because she's too impatient for coraline spread-2-3 times per week, as well as ~10% wc with the IO salt every weekish. My CA, dKH, and MG have been consistently in the area I posted before since switching to IO salt, even with the dosing. The entire time I was using oceanic my dKh was at least 18, typically 20+ and I never had any issues, my mushrooms and candy canes thrived at those levels in my 20g nano I had before. I do want to reiterate, when I had 600+ Ca and 20 dKH, i was NOT supplementing anything. bertoni, When I test a new batch of salt, it typically reads at 1.025. As far as pH, I have a Milwaukee "lab" pen type probe.I have not been too suspicious of it being inacurate because my API liquid test is fairly close-and we all know those liquid tests can be difficult to interpret. I check my pH daily with the probe, and when I pull water for my weekly tests, I do the liquid test for the hell of it-I'll also do a liquid test if I think the probe is way off. When I do the liquid test, I do 3-4 tests. I throw out the first-because the first one is always way high or way low off the chart either way-then do 2-3 more and take an average of those readings-they're typically identical.

06/28/2013, 10:14 AM	#6
aakour Registered Member Join Date: May 2013 Location: Stillwater, OK Posts: 27	I've considered building a scrubber, just been trying anything else I can before building or adding anything else that needs consumables.

06/29/2013, 09:48 AM	#8
aakour Registered Member Join Date: May 2013 Location: Stillwater, OK Posts: 27	Ok, I will try that over the course of the next few weeks or so, I only have to top off about 1gal/week.