Possible causes for GHA bloom in healthy established tank

[Julian.Rad17]

My tests results for nitrate and phosphate have consistently read very close to zero for at least a month now, (Hannah checker, salifert) but hair algae continues to thrive. I scrub it off the rocks when I can but it grows back within the week. However, my pH has been in the 7.8 range for a while which I am thinking may be because of my NOPOx dosage (3ml) and the excess bacteria it creates which are most likely consuming the oxygen in the water and therefore lowering the pH. My question is, will increasing the pH limit/stop the algae growth, or have I overlooked other possible causes? All coral doing great/growing, acros, lps, which I find weird in the midst of all the algae. Windows in the room are always open to allow for O2, and I've also tried baking soda to raise the pH.

Weekly 20% water changes. GFO in filter bag, RoDi system, 20 gallon tank 3yrs old.
Alk 8.5
Cal 480

[j.falk]

Are your rocks possibly leaching phosphates (a common issue that fuels hair algae growth)?

[ThRoewer]

No competition and nothing that eats them.
Algae don't need high nitrates and phosphates to thrive, they do just fine in a low nutrient environment.
There is of course also the possibility that the nutrient levels are low because of the algae.
Get a good number of trochus snails and Scarlett hermit's to combat the algae. I had a 40B tank overrun with GHA. To clean it up i added 75 Trochus snails and 30 hermits and within a month the tank was alga free.

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[Julian.Rad17]

Originally Posted by ThRoewer

No competition and nothing that eats them.
Algae don't need high nitrates and phosphates to thrive, they do just fine in a low nutrient environment.
There is of course also the possibility that the nutrient levels are low because of the algae.
Get a good number of trochus snails and Scarlett hermit's to combat the algae. I had a 40B tank overrun with GHA. To clean it up i added 75 Trochus snails and 30 hermits and within a month the tank was alga free.

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In addition to a better cuc, i think i need to address the problem of low ph. Do you know of other ways to raise it because i've had no luck so far.

[hegeh]

Why is ph bothering you? It wont cause any significant effect on ur reef.

Those GHA can live on low nutrients. So cuc will help to clear them off.

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[Julian.Rad17]

Originally Posted by hegeh

Why is ph bothering you? It wont cause any significant effect on ur reef.

Those GHA can live on low nutrients. So cuc will help to clear them off.

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Because at a ph of 7.8 there is about 3 times more CO2 in the water than at 8.3 which I think is significant. I have to limit the algae growth somehow before i rely on snails to eat it. It grows too fast and long for them to be able to compete anyway.

[ThRoewer]

Originally Posted by Julian.Rad17

Because at a ph of 7.8 there is about 3 times more CO2 in the water than at 8.3 which I think is significant. I have to limit the algae growth somehow before i rely on snails to eat it. It grows too fast and long for them to be able to compete anyway.

You have it wrong: it isn't the low pH that gets the CO2 into the water but rather the CO2 that gets absorbed into the water is the cause for the low pH.

Temperature, salinity, and the amount of CO2 in the (room) air would be the factors that determine the CO2 uptake by the water.

If CO2 is a concern you would need to add a CO2 scrubber to your air intake lines. And maybe vent the room better.


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[hegeh]

You may also consider algae scrubber.. which allows algae to grow in sump rather than display tank. Apart from that, it gives O2 at which increases your Ph as algae gives off oxygen

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[Julian.Rad17]

Originally Posted by ThRoewer

You have it wrong: it isn't the low pH that gets the CO2 into the water but rather the CO2 that gets absorbed into the water is the cause for the low pH.

Temperature, salinity, and the amount of CO2 in the (room) air would be the factors that determine the CO2 uptake by the water.

If CO2 is a concern you would need to add a CO2 scrubber to your air intake lines. And maybe vent the room better.


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Yes I agree and am aware of how the CO2/pH process works

[PurpleCarpet]

Lawnmower Blenny can decimate GHA as well. Though finding the root cause is always the best solution.

[mikeatjac]

Who wants a large CUC. What has always worked for myself and friends is to raise ALK to 10 with a small addition to their CUC. This process has never created a problem with a SPS tank.

[bshow24]

If you're using GFO, have low readings of phosphates (albeit could be due to the algae taking it in) and are scrubbing it only for it to regrow, I wouldn't be surprised if the rock is leeching phosphates.

I had some GHA explosions recently due to a lighting adjustment. All I did was put my macro algae reactor back online to help compete and threw some turbo and ceriths in, within 10 days the algae was gone.

Lastly, your ph is fine as long as it's staying consistent. Chasing ph is one thing you shouldn't worry about. Unlike alk, calc, n/p, all you need for ph is a number above say 7.7 and be consistent. If it was too low, it would be affecting your corals.

[CAPT_Dave]

When you do scrub it off the rocks, you have to get it out of the tank. Net it, suck it up during water change, etc. If you leave it in there it will release all those nutrients back into the tank when it dies, feeding the next generation.

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[laverda]

My guess is your nutrients have been slowly climbing for a while causing the gha. It is very common for Po4 and No3 to read low during an algae out break as they are consuming it. I find an ATS works wonders at keep algae out of my display tank. They are easy and inexpensive (less tan $30.) to make and can fit just about any tank easily. See my DIY algae scrubber thread for some ideas.
I don’t think your PH is the cause, although I have read algae does not do well at PH above 8.4. Baking soda will not raise you PH unless it is very low. However baked baking soda a will. Spread some out on a cookie sheet an bake for an hour at 400.
What are you using for filtration?

[droog]

Originally Posted by Julian.Rad17

In addition to a better cuc, i think i need to address the problem of low ph. Do you know of other ways to raise it because i've had no luck so far.

ph is basically function of Alk and CO2 (I know you know this).

Increasing Alk to fix ph doesn't really make sense and despite the name there's no such think as a ph "buffer" - those products are simply alk additives.

So you're left with CO2 as the only "independent variable" in the equation. In order of simplicity you can

1] Ventilate the room better (open windows, and/or run AC)
2] Have the skimmer inject air from outside (run a line from skimmer air intake to outside, or some kind of fan assist to get fresh air to the vicinity of the skimmer intake)
3] Run a C02 scrubber on the air intake to the skimmer
4] Have a beer and/or watch the tank and forget about ph

The ph problem tends to be worse in new homes (because they are well sealed) or basements (because they have poor ventilation).

If you search on this forum there are plenty of examples of people that have done [2] and/or [3]. Typical results seem to be a .1 or .2 improvement in ph. Personally I think only [1] and [4] make sense...

My place is old and drafty, so ph is not a problem :-)

-droog

[lionfish300]

4 it is lol