Convinced of a link between GFO and Cyano (and not the good kind)

[Myka]

What you're describing is common phenomena. The cyano bloom happens in our tanks from GFO for the same reasons it happens with biopellets - quick, significant lowering of phosphate. In other words, too much GFO (or too aggressive with biopellets). It can happen with Lanthanum chloride (FozDown) too for the same reason. It doesn't happen in every tank though under what appears to us to be similar circumstances which is obviously frustrating. Just as frustrating as high nutrient SPS tanks that get no waterchanges or dosing and grow SPS like weeds for years and years (lol). Anyway, the reason the cyano appears is because the water column is suddenly barren of phosphate yet the substrate and rock is still loaded. As the phosphate leeches out of the substrate and rock the cyano jumps in to feed off it as it leeches. Cyanobacteria are extremely efficient at processing phosphate.

The fix: Pull the GFO. Keep using carbon. Add a filter sock, then use a piece of rigid airline tubing with flexible airline tubing attached to make a mini siphon hose and suck the cyano out of the tank at the peak growth of the day (usually at peak lighting). Do this daily or every second day. After you suck out as much as possible use a turkey baster to blast every nook and cranny in the rock. Then use a feeding stick or the baster to stir up the top 1/2" of sand. Wait an hour and remove/change out the filter sock. It takes elbow grease, but it's very effective.

Next time, don't use so much GFO. 1 tbsp per 30 gallons changed out every 2-3 weeks is much "safer" than adding a whack and changing it out every 6-8 weeks.

Added note... in my experience, mature tanks shouldn't need GFO, and usually do better without it.

[MitchM]

Originally Posted by Myka

... Anyway, the reason the cyano appears is because the water column is suddenly barren of phosphate yet the substrate and rock is still loaded. As the phosphate leeches out of the substrate and rock the cyano jumps in to feed off it as it leeches. Cyanobacteria are extremely efficient at processing phosphate.

....

Right. The cyano will also appear on dying macro algae.
You'll still have to siphon the cyano out as it appears, if it does.

The key is keeping phosphate out of the water column in the long run. I'm finding it easier to dose Foz Down, it's a lot less hassle than GFO and I can instantly tweak the dosing to match my feeding schedule.

[monza]

Originally Posted by MitchM

Right. The cyano will also appear on dying macro algae.
You'll still have to siphon the cyano out as it appears, if it does.

The key is keeping phosphate out of the water column in the long run. I'm finding it easier to dose Foz Down, it's a lot less hassle than GFO and I can instantly tweak the dosing to match my feeding schedule.

So is your filter sock just in the water or do you have flow of some sort running through it?

[MitchM]

I have a CPR 4 inch sock holder mounted inside the sump with a maxijet 600 pumping sump water into it.
The dosing tube drips into the filter sock.

[gregzz4]

Originally Posted by Myka

Next time, don't use so much GFO. 1 tbsp per 30 gallons changed out every 2-3 weeks is much "safer" than adding a whack and changing it out every 6-8 weeks.
Added note... in my experience, mature tanks shouldn't need GFO, and usually do better without it.

So, you're advocating using roughly 50mls of GFO in my 105 system, instead of the BRS recommended 225mls ? ( For my tank they recommend 0.86 cups )

Your ammount equates to;
105/30=3.5 Tbsp
3.5x15mls(Tbsp)=52.5mls

I get all the hype about selling product and such, and some may not change their media when they should, but that's a big difference

I'm asking as I'm considering your recommendation for 3 reasons;
1 - I have GHA that I suspect is living off the iron from the GFO
2 - My corals have become 'too green' after the last GFO I bought
3 - I'm looking to cut costs

I'm also considering cutting GFO out of my tank's diet altogether as it's getting old enough now

[Myka]

Originally Posted by gregzz4

So, you're advocating using roughly 50mls of GFO in my 105 system, instead of the BRS recommended 225mls ?

Yes. I've had better results in the tank by using a lesser amount and changing more often.

I just looked at BRS, as I'm not familiar with their recommendations, and I see they want you to change it out every 4-8 weeks.

To compare my recommendation to BRS:

My recommendation is 1 tbsp (15 mL) per 30 gallons changed every 2-3 weeks. So my recommendation on 105 gallons works out to 140-210 mL in 8 weeks. I use RowaPhos strictly. I haven't used BRS HC GFO in several years.

BRS recommendation of 225 mL of the HC GFO changed every 4-8 weeks is 225 mL to 450 mL in 8 weeks.

There is almost no data available to compare the different brands of GFO, although I have found one comparing RowaPhos to PhosBan. http://www.theaquariumsolution.com/f...n%20report.pdf

Ultimately, my recommendation is based on using RowaPhos, and I am not sure if my recommendation can be directly compared.

[gregzz4]

Originally Posted by Myka

Yes. I've had better results in the tank by using a lesser amount and changing more often....

Thanks Mindy ( I missed your post )

I've been using 225ml and changing it every 2 weeks
I'll try cutting it in half to start with and see what happens with my PO4 readings/algae issues

If all is good I'll keep cutting it back to a point where I know what amount to use every 2 weeks