High Mg and GHA

Anyone know if there is a correlation between high Mg levels and outbreaks of GHA?

 

Can you provide more specifics regarding the your mag level and how long you have had a problem with GHA as well as tank age if appropriate.

TIA

 

Yes, thank you Corailline. In an attempt to rid my tank of Bryopsis, I raised the Mg. level in my tank to 1700 ppm. I have read that by doing this it would kill off the bryopsis. Of course this was not the only thing I had to do. I removed all of the rock/corals affected with the bryopsis from my tank. Removed (pulled off/brushed off) as much of the bryopsis as I could. I then returned the rock/coral back into my tank. I cleaned my power head and return pump by soaking them in vinegar. I then replaced all tubing and hoses. After all of that, I conducted a large water change. I then began to slowly (90 ml per day) raise my Mg level using Kent's Tech-M. This process took approximately 2 weeks to reach the 1700 ppm. So far, so good. After 3 weeks I have not seen the return of the bryopsis. However, while waiting to see if the bryopsis would return, I noticed a bloom of GHA starting to appear. My parameters are; NH3-4=0.000, NO2=0.002, NO3=1.0, PO4=0.01, SiO2-3=0.0, Ca=395, Alk=3.20 Meg/L and Mg=1688. I use RO/DI water for all top-off and water changes.

Once a month, I send a water sample to Aquarium Water Testing as a control for the testing I do myself. Because of the elevated level of Mg (1688) determined by AWT, I was informed (by AWT), that elevated levels of Mg could encourage algae blooms. It is because of this statement by AWT, regarding the Mg level, that I posed my question. My tank is a 90 gal. reef and is a 10 month old work in progress. Thank you for your help.

 

Great detail!

Have you considered that you are seeing the development of GHA because the phosphates that were bound up in the Bryopsis became present and available in the water column as the Bryopsis died back?

Are you currently or have you tried any phosban, GFO or other such media that removes phosphates.

Sounds like you have a great handle on the situation.

I imagine or at least hope that the GHA will die back as well, with the absense of excess nutrients, and as time goes on. With all the water changes you are doing and making sure the addition of phosphates is limited you should seem some improvement in a couple of weeks.

Good luck

 

I had my Mg level at 2000 to get rid of bryopsis. I didn't have a huge amount, but it took a while for it to go away. I didn't have a HA problem, but had some snotty looking dino instead. The dino has run it's course and is 99% gone on it's owm. I think the same thing will happen with your HA, just a temporary short cycle thing. I also run GFO and do a three day lights out every couple of months.

 

Thank you Corailline. I think you may be correct about the phosphates . I did notice a slight increase in phosphates after the bryopsis began to die off. I do use GFO, in a reactor. And, I though I was feeding very little but will cut back on my feeding routine anyway. Thank you for your response and encouragement.

 

Thank you barbianj. Thats encouraging. I think I might try the 3 days, no lights also. Have you had a recurrence of the Bryopsis?

 

I didn't take the rock out and scrub it like you did. After it started getting weak from the Mg, I pulled it off of the rocks, did a wc, then 3 days with no lights. That put it over the edge and it receded. The high Mg alone was not going to do it like others have claimed, at least IME. There are still a few tiny spots with bryopsis, but I haven't seen it growing.

The lights out is beneficial on it's own. I've seen nothing but positive results from it, and plan on doing it on a regular basis.

 

Thanks barbianj. Sounds like you have a handle on it. And, I do like the lights out for three days too. I'm will be doing that for sure.