I have never tried spot dosing glut, but all the threads I've read say it does work. After all, glut is a sterilizer, and Cyano is a bacteria.
Each thread has had one person complaining that spot dosing glut did not work for them. But since it has only been one person in each thread, I've considered their experiences to be caused by user error.
Im trying the whole tank approach at the moment. Removed all the glute sensitive plants for the experiment.
Seems excess phosphate, and nitrates are a possible cause for BGA. But in a planted tank that is dosed with the very elements that might aid in BGD forming creates a conundrum. I run my planted tanks at about 5PPM of PO4, and around 10PPM of KN03. I am going to maintain the same levels so I will know for sure if the glute is working, and not a reduction in ferts.
I'm not sure it will work that way. I am dosing twice the amount on the instructions, and I still did get a small patch of BGA. I am dosing 2 mL per day, on a 10g tank. Infact, there is a TINY dot of BGA starting back up.
I'm leaving it there, because my sister may need it for her micro-biology lab. XD
I'm not sure about the whole tank treatment being effective either. I dosed 1/4 cup to a 40 gallon breeder tank. I should see results in about 72 hrs. if this treatment method is going to be effective. If mild results are noticed, then I will increase the dosage somewhat. Fortunately there is no livestock in this tank, and the plants are nothing rare, or even remotely valuable.
If it does work in a non stocked tank, then the proper dosage will need to be figured for a stocked tank, to eradicate the BGA, but not harm livestock.
The Cyno is completely gone from the tank. The glute worked, but took a high concentration. I spot treated a few spots and it was gone in just a couple days. Treating the whole tank took about 5 days to eradicate the cyno.
I just came across this thread so sorry for the late reply.
I believe by 40B he is referring to a 40 Gallon breeder tank 36" wide, 18 deep and 16" tall.
I have had concessional blooms of cyno bacteria in the past and found three different approaches for clearing it up.
1. Reducing the amount of light the tank is receiving in the red part of the spectrum. Bhis is a matter on a florescent tank to simply switch out one of the daylight bulb I normaly ran with an atinic bulb for a few days till it was gone. With the plants still getting 1/2 the normal amount of red light and much more green light they would not show any problems with this.
2. Stop all fertilizer dosing for a few days. Again the plants can handle the lower neutrament level much better and longer than the Bacteria can.
3. As prior mentions dosing with Erthoimyiacine (sp?). This was usualy the quickest fix with the tank usualy being cleared up completely in 48 hours. Once it was cleared up I'd do 20% water changes every day for about a week.