troubleshooting tank

[lumpy]

I'm running a 75 gallon tank. 6 bulb T5 lighting setup.
2 white day glow lights on for 4 hours a day.
2 actinic blue lights on for 12-16 hours a day
1 violet light on 12-16 hours a day
1 red or pink light on for 4 hours a day
Tank has been running for about a year now.

I'm changing out 5-10 gallons every weekend.
Water test is showing
0 Nitrite
0 Nitrate
0 Amonia

Although I had some Nitrite .25 - .5 range prior to the skimmer fix last week.

Salt is between .025 - .030.
Calcium is at about 460

I know for a while my skimmer pump was underpowered but I've beefed it up significantly and I just received a bubble blaster pump in the mail that should take it up even further.

For some reason I'm getting die back on my corals. Most noticeable with Gonripora, and Frogspawn although I'm noticeing some on my Hammer Coral too.

I've also noticed a large increase in cyano.

I think I've lost a good sized chunk of my clean up crew as well with the exception of some hermits and trochus snails.

Is the loss of the clean up crew likely to be a large factor in the cyano outbreak? Is there anything else I can get a test kit for that might help me determin if I have a water quality issue? Is part of my issue my lighting? Could the cyano be responsible for the coral die back?
I'm really kind of stumped on where to look next.

 

[salt_for_brains]

What are you checking your SG with hydrometer or refractometer? That needs to stay more consistent at 1.025.
What is your ph and alkalinity running?
How old are your bulbs?
I would run the white lights a couple hours longer but reduce the overall lighting period to 10 hours and see how that works.
Are you using RO/DI water for water changes and top offs?
How much flow do you have in the tank?

 

[salt_for_brains]

How often are you feeding? If you are feeding any flakes or pellets they contain a lot of phosphates so try and stick to quality frozen foods. You can also test for phosphates with a test kit.
When you do your water changes suck out all the cyano you can. Also direct some flow in those areas by adding or pointing an existing power head in that direction.

 

[lumpy]

Checking SG with refractometer.

PH is 8.0

The two whites are brand new. the actinics are ready for replacing. Their my next item on the budget..

I'm using RO/DI for changes and top offs.
I'm running two powerheads on the back wall of my tank, Both are 5 seconds on then 5 seconds off using a wave maker.

 

[lumpy]

How quick can I expect the cyano to clear up?

I'll redirect the powerheads and try to get a phosphate test tonight.

Feeding with frozen food and Algea sheets. Twice a day for frozen. One Algea sheet per day or two. Plankton for the corals once to twice a week.

 

[salt_for_brains]

What fish do you have in the tank? Are you feeding whole cubes at a time? Sorry for all the questions but it seems you are putting a lot of nutrients in the tank which is fuel for the cyano.

 

[lumpy]

yep whole cubes.

I have the following fish
lemon yellow tang
bengai cardnal
2 clown fish
2 wrasse
2 gobies
blue damsel
green damsel
and a redbarred hawkfish.

is a whole cube all that much food? It doesnt seam like much.

 

[fastrd400]

You are feeding wayyyyyyy too much. Once every other day is enough, and about half of what you are using.

 

[lumpy]

oh. Well I guess that would cause the cyano bloom then.

 

[BL1]

You definitely need to lock down your salinity. The swings you're having can definitely be the culprits for your inverts and corals declining. Also, 1.030 is way too high, your salinity should never go higher than 1.026.

As far as your feeding, I'd cut back like Fast suggested and I'd cut the algae sheets ba I to 1/4 of a sheet every other day. Another issue for your excess nutrients is your stocking, 11 fish is a lot IMO for a 75g.

 

[2XAl]

I wouldn't be as concerned with the number of fish if you have a kick ass skimmer and are strict on water changes. not saying i agree but i nave a friend with at least 11 fish in a 55 and his tank is pristine. Two wrasses in one tank may lead to aggression IMHO. You are Definitely feeding too much, I have 8 fish we feed a half cube every other day and prob an 1/8 of a sheet with it.