New tank ph lowering possibly due to cycling

[SeaTila]

Two weeks ago...Moved to 200g tank with all new red sea reef coral pro water dosing with stability. A lot of Live rock from old tank. Calcium 420, nitrite 0, nitrate less than 10ppm, alk 120ppm, ammonia not showing up. Havent done phosphate test

Noticed diatoms and green hair algae a week ago and radions were pretty intense at 85%. Ph started to drop but alk was about 100ppm and skimming on. Gyre working at pretty good clip. Lots of circulation.

My skimmer was giving trouble for first couple of weeks and not working well until last 3 days.

Added airstone about 5 days ago and reduced lights to 40%...and ph climbed back to over 8.0 quickly.

I removed the airstone a couple of days ago thinking it was not really needed but just noticed the ph lowering a lot again.

I just moved the radions to 55%. Ive been dosing liquid reef at 10ml every other day.

I know the tank has to cycle so not sure if I need to add airstone back or if I should be doing anything else. I have 1 tang, 1 longnose hawkfish, goldenhead goby, 2spot candy hogfish, clown, anemones, few sps, emerald crabs, blood cleaner shrimp, coral banded shrimp. All appears to be fine and getting along.

Does anyone have any ideas on if I need to do anything to help the ph? Should I add airstone back? Skimmer too small? Lights on longer? Add buffer daily as short term fix?

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[SeaTila]

My skimmer is small for the 200g...its a octopus 120g from old tank. Its producing bubbles so dont know it getting a bigger skimmer will fix this or not if o2 issue.

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[gone fishin]

From your post it sounds like maybe your CO2 is a bit elevated. Is your waters surface being broken for gas exchange?

Also, if I did my conversions correctly on your alkalinity from ppm to dkh(what I use) it would seem your alk levels may be on the low side. Double check but you may want to try and get your alk up to around 140ppm. Good luck

 

[CStrickland]

I don't see in your post how low the ph is going?

Either way, it's probs fine but there's no harm in leaving the airstone if you like.

Also I'd test your magnesium. Dosing stuff like "liquid reef" can get tricky because it's supposed to be all in one but if your mag is low the ca and alk won't stay dissolved in the water no matter how much you add.

 

[SeaTila]

Here's a few pics. There's a good amount of movement and u added the airstone as a precaution.

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[SeaTila]

I don't see in your post how low the ph is going?

Either way, it's probs fine but there's no harm in leaving the airstone if you like.

Also I'd test your magnesium. Dosing stuff like "liquid reef" can get tricky because it's supposed to be all in one but if your mag is low the ca and alk won't stay dissolved in the water no matter how much you add.

I will test mag and all others tomorrow am. Good point. The liquid reef is a short cut. I didnt realize the mag level could cause this and assumed liquid reef would be balanced ca/mag. The last ph I checked a few hours ago is 7.5 to 7.7 and super-low compared to usual 8.2+ usually see. Anticipation it may lower more overnight due to lights dimmed has me concerned.

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[SeaTila]

From your post it sounds like maybe your CO2 is a bit elevated. Is your waters surface being broken for gas exchange?

Also, if I did my conversions correctly on your alkalinity from ppm to dkh(what I use) it would seem your alk levels may be on the low side. Double check but you may want to try and get your alk up to around 140ppm. Good luck

I usually just water change often and dose trace elements, liquid reef. I have mag/ ca etc. How do you raise alk?

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[gone fishin]

I usually just water change often and dose trace elements, liquid reef. I have mag/ ca etc. How do you raise alk?

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Before you get into dosing the alk, like CStrickland mentioned check your Magnesium. Mag is used slowly but it is does a lot chemistry wise. If your interested in learning what it does there are some articles in the reef chemistry forum stickies. For now we will just say that it provides stability to the alkalinity and calcium. Also, verify that your salinity is not to low.

If you decide that you need to start dosing for alkalinity then you can try either kalkwasser in your ATO or you can do 2 part dosing for alk and calc with dosing pumps. BRS has a nice little 2 part kit that I have used for a few years.

 

[SeaTila]

Before you get into dosing the alk, like CStrickland mentioned check your Magnesium. Mag is used slowly but it is does a lot chemistry wise. If your interested in learning what it does there are some articles in the reef chemistry forum stickies. For now we will just say that it provides stability to the alkalinity and calcium. Also, verify that your salinity is not to low.

If you decide that you need to start dosing for alkalinity then you can try either kalkwasser in your ATO or you can do 2 part dosing for alk and calc with dosing pumps. BRS has a nice little 2 part kit that I have used for a few years.

Thanks. Salinity is consistent 1.025. Temp is 79. I dosed mag a bit last night as precaution. I'll get numbers this am. It does appear the numbers easily drop compared to the more established 120g I was running.

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