Cyno... Again... Need breakdown or treat advise

[Number1cookie]

Had a cyno outbreak back in September while I was cycling my tank. Treated for 5 days, went away. 8 months later and it's back. It is on my swords, on the sand and from looking at the side of the glass it's under the sand. (It's PFS). I am seriously frustrated with this crap lol

37 gallon tank

Fish:
2 angels
3 nitrite snails

Plants:
3 amazon swords
Anubias
A couple telanthera cardinals

Options I need help deciding on:

1. Treat my tank again with meds for 5 days and see what happens

2. Move my angels and nerites to another tank and completely tear this tank down, get new substrate and plants and start over??? If I move my angels to my 55 gallon there are black skirt, head and tail light, and red minor tetras in there, will they be ok there? If I do this I want to really do a better planted tank (convicts is very inspiring haha) plus my birthday is soon so I can splurge a little

Not sure why I got the cyno again, I am careful with feelings, I only use root tabs right now and it's been about 2 months since I have replaced those. Light is a t8 and it is on a timer for 2 hours in the morning and about 3 hours at night (scheduled around the times we are home so we can see everything lol)

Ideas? Suggestions? What would you do if it where your tank?

 

[Rivercats]

What are your nitrate levels? Often if nitrates drop below 10ppm cyano can rear it's ugly head. Just remove as much of it as you can and then do the the erythromycin treatment.

 

[aqua_chem]

A second occurrence after a completed course of antibiotics strongly suggests that there's something at work that's actively causing an environment that favors BGA.

What is your flow, nitrates, WC schedule, lights, and ferts?

 

[Number1cookie]

Just tested my nitrates again, sitting right around 20, water flow is just from my HOB filter (my angels have just now gotten big enough to be able to swim around that lol), I do 50% water changes every weekend, light is a t8 plant bulb I got from petsmart, I only use root tabs and its been close to two months since I have put new ones in.

 

[Number1cookie]

I am going to pick up the meds today, still undecided if I don't need to just break everything down and start over.... Do you think it could be water flow? With angels in the tank what could I add to help add that? It is showing up more on the side of the tank that the HOB filter is on as well.. It is a 37 gallon tall.....

 

[Rivercats]

I have 12 adult angels and have significant water flow which doesn't bother them. I use these nano powerheads in my tanks which are great for moving water but not blowing everything away... Amazon.com: Hydor Koralia Nano (Mini) Pump/Powerhead 240gph: Pet Supplies

 

[Number1cookie]

Thanks, I will see about picking one up, that will help rule out water flow as a cause