View Full Version : low ph

05-15-2009, 12:55 AM
We borrowed an electronic ph tester because we weren't trusting our api test and turns out its right. The tester is calibrated so thats not the issue, but our ph is 7.8 and its less then an hour before lights out. I'll test it in the morning to see how much of a swing we get, but why would it be so low. Alk is 10, calcium 440 and mag 1350 and it gets plenty of aeration. I've read that a low ph is ok if you maintain decent ALK, MAG, and calcium lvls, but is this true? Everything seems to be doing great except for the birdsnest and purple cap, and the purple cap is actually starting to recover. I just don't want to start messing with ph unless is absolutely necessary. Thank you for any input. We also discovered some odd results with our freshwater tanks which I am making a seperate post about.

05-15-2009, 01:05 AM
do you have a lot of macro algae in your refugium?

05-15-2009, 01:16 AM
We do. We have chaeto, caulerpa, and a little bit of Purple Ochtodes. The lights for the refugium run on a reverse schedule. The display lights are from 10 am to 10 pm and the refugium lights are on from 10 pm to 10 am

05-15-2009, 01:24 AM
The caulerpa is a fast growing macro algae and as such it photosynthesizes at a higher rate. That large amount of Macro algae is no doubt resulting in a large amount of CO2 being respired into the water during the day. Personally I only use a small amount of Chaeto in my refugium. I have enough Chaeto to fill about a 2-3 cup measuring cup, and I have no pH swings at all. I run my refugium on the same schedule as my lights. The use of macro algae in refugiums is really way over rated. It helps some with nitrate reduction, but IMO, not enough to make a huge difference. I have enough live rock to handle my biofiltration, the only thing my refugium does is create a growing place for pods.

05-15-2009, 01:42 AM
That makes a lot sense, because our alk is normal, so in a perfect world our poh should be too., but with too much co2 being put back in during the day that would certainly keep the ph low. We only have about as much chaeto as you mentioned and the rest is caulerpa. So we should give away the caulerpa and see how that helps. Thank you

05-15-2009, 02:02 AM
You have the same amount of Chaeto in your small tank as I have in my 125, and I have a larger biomass of corals. LOL You definitely do not need as much as you have. I'd also get rid of the Calurpa for another reason; Calurpa is more likely to go sexual than any other Macro Algae. Chaeto, on the other hand, will not go sexual and is why it is the best and most popular choice for refugiums.

05-15-2009, 02:22 AM
I removed half the Calurpa now. I'm going to wait and see if anyone locally wants the rest before removing that too. I'm also going to ditch the mangrove that I forgot to mention:ssuprised: I bet its not helping either. No one wants it locally so I think I'm going to have to toss it...unless someone here wants it

05-15-2009, 11:10 AM
It only dropped down to 7.6 during the night so there isn't much of a swing. I removed a lot of macro last night so I'll see if it gets any higher by tonight

05-15-2009, 12:17 PM
You guys don't smoke do you?

05-15-2009, 02:00 PM
Nope, and we have an electric stove and our house heaters, which are off now, are vented outside. I removed a lot of macro last night so I'll see if it increases the ph by the end of the day.