Phyto raising pH?

[Strad12]

In an attempt to build a strong food chain in my reef (10G Nuvo), I've been dosing phytoplankton and copepods for the last month (2mL every other day). About a week ago, the tank started getting some algae and diatoms (the tank is just under 2 months old), so I upped the dose of phyto (2mL daily) hoping that they would consume nutrients faster than the hair algae. Around the same time, I noticed the pH was higher than normal, up to 8.4-8.5 during the day. I was slightly concerned, but I chalked this up to not having any fish in the tank and Kalkwasser on the ATO. About a day or two later, I started seeing brown slime with bubbles attached to it popping up on the rocks. It looked a lot like Dinos, so I upped the phyto dose even more (3-4mL daily) and fed some Reef Chilli and Red Sea AB+. Now the pH is around 8.7 and there are lots of little bubbles on the rocks and some brownish green slime connected to them along with diatoms and some algae. I cleaned off the rocks with a toothbrush and did a 1 gallon water change yesterday and didn't dose phyto, and it seems to be better today, but still bubbles on the rocks. The corals have great polyp extension and noticeable growth from last week, so I'm not planning on taking any corrective measures other than giving the phyto doses a rest for a week.

My question for Randy: Did the excessive phytoplankton dosing raising my pH by consuming all of the CO2 in the water and releasing a lot of O2 in the process?

 

[ichthyogeek]

Question: are you running a skimmer? What phyto brand (if home culturing, species?) are you dosing?

 

[Sdot]

In an attempt to build a strong food chain in my reef (10G Nuvo), I've been dosing phytoplankton and copepods for the last month (2mL every other day). About a week ago, the tank started getting some algae and diatoms (the tank is just under 2 months old), so I upped the dose of phyto (2mL daily) hoping that they would consume nutrients faster than the hair algae. Around the same time, I noticed the pH was higher than normal, up to 8.4-8.5 during the day. I was slightly concerned, but I chalked this up to not having any fish in the tank and Kalkwasser on the ATO. About a day or two later, I started seeing brown slime with bubbles attached to it popping up on the rocks. It looked a lot like Dinos, so I upped the phyto dose even more (3-4mL daily) and fed some Reef Chilli and Red Sea AB+. Now the pH is around 8.7 and there are lots of little bubbles on the rocks and some brownish green slime connected to them along with diatoms and some algae. I cleaned off the rocks with a toothbrush and did a 1 gallon water change yesterday and didn't dose phyto, and it seems to be better today, but still bubbles on the rocks. The corals have great polyp extension and noticeable growth from last week, so I'm not planning on taking any corrective measures other than giving the phyto doses a rest for a week.

My question for Randy: Did the excessive phytoplankton dosing raising my pH by consuming all of the CO2 in the water and releasing a lot of O2 in the process?

Im curious...when was the last time you calibrated your PH probe?

 

[Strad12]

pH probe was last calibrated a couple months ago. I have 2 tanks, both ~10 gallons, both running Kalkwasser. One tests between 8.1-8.3 depending on time of day, the other is between 8.4-8.7 with the same pH stick from Milwaukee Instruments. The tank with the lower pH has 2 clowns and a goby, and much more coral. The high pH tank has no fish and 12 Acropora frags in it.

The phyto culture was purchased from someone on R2R. I haven't dosed it the last couple days, and the brown slime and bubbles on the rocks have disappeared, but the pH is still running on the high side.

 

[Randy Holmes-Farley]

My question for Randy: Did the excessive phytoplankton dosing raising my pH by consuming all of the CO2 in the water and releasing a lot of O2 in the process?

Live phyto may photosynthesize and raise pH by consuming CO2. The effect on O2 will be small but real.