Help: SPS bleaching and STN

[Myka]

I would suggest you go to a water store and buy 40 gallons of RO water and do a couple 20-gallon water changes in the next week. Also, with STN I find a lower alkalinity level is often better. Your calcium and alkalinity aren't balanced btw either.

If you have too rigorous algae growth in your tank it will starve your corals of nutrients causing bleaching. Algae also release toxins of sorts that inhibit coral growth and can really harm corals if it is out of control. I've experienced this myself.

Another thought is that I don't think those MP10s are really strong enough on that size tank for SPS. I think it would have been better to buy two MP40s. If you have any more powerheads on hand you could try adding more flow.

For feeding, feed the corals in the evening jut before lights out and turn the pumps off for an hour so they can feed. Then by morning the food will be filtered out by your skimmer and filter sock. Filter socks tend to really help with cyano if you change them out every 2 days.

Thanks for the tip Mindy. I'll give those suggestions a try.

[asylumdown]

how are you maintaining alkalinity? Are you using an auto-doser? I had problems like this on my old tank when my alk levels weren't stable over the long term.

I am using a bubble magus dosing pump, dosing two part. Using baking soda (arm and hammer).

[gregzz4]

Originally Posted by Myka

Another thought is that I don't think those MP10s are really strong enough on that size tank for SPS. I think it would have been better to buy two MP40s

You think 4 x MP10s isn't enough for a 70G tank ?

I'm running 2 x 10s in my 75G and can't run them @ 100% without either blowing flesh off corals/polyps stop growing on one side, or causing them to grow sideways away from the props

[lastlight]

i've got 2 x mp10s in my 93 cube and they're at 70%. All my SPS are happy.

[Myka]

Originally Posted by gregzz4

You think 4 x MP10s isn't enough for a 70G tank ?

I'm running 2 x 10s in my 75G and can't run them @ 100% without either blowing flesh off corals/polyps stop growing on one side, or causing them to grow sideways away from the props

I don`t think you`re setting your powerheads up very well then. Certainly you can`t place powerheads so they shoot directly at corals. The MP10s are only 1500 gph full blast which isn`t enough to push across a 48 inch tank. If the MP10s were situated on the back glass pushing towards the front more velocity may be able to be made. SPS though need a lot of water movement throughout the tank and appreciate velocity.

My 90-gallon which is very similar dimensions to a 75-gallon has two Tunze 6105 (3400 gph) and a 6055 (1450 gph) and I can run all of them full blast with the narrow outputs on them and as long as I have the powerheads situated well my corals will keep their flesh on. My tank has about 92x turnover where the OP`s tank has about 80x turnover. Even though these numbers are quite similar, the larger pumps in my tank create higher velocity.

The Tunzes`new wide flow output option is really cool because you can get the same amount of flow with less velocity. LPS do not appreciate velocity. In a mixed reef like the OP`s, creating flow that makes all the corals happy is challenging.

Chizer, I would try moving those MP10s around to create more velocity near the SPS. If you set them up on the back glass pointing towards the front glass you should be able to achieve this. The VorTechs can be a bit awkward though since you can`t control their direction.

It could very well be the tap water though.

I wish that was an option. I have a large coast to coast external overflow on that entire back wall so it limits me to placing the MP10's at the bottom half of the tank. I had thought about building my rock up with PVC and laying them on egg crate, then it would give me that velocity.

What do you think? Will this look tacky? My SPS will then be about 6" from the surface.

I am going to buy a RODI unit from BRS. Just looking at the cost of RO in my city, it's going to be $40 just to do a 40 gallon water change. That's not including the ATO water of 15 gallons a week.

Also going to try some BRS GFO in a media bag, in my filter sock. But I'll put it on the output of my protein skimmer.

I really want to get a way from carbon dosing entirely. It's scaring me off.

I am thinking it was a combination of ALK ( initially at 7 and then I slowly raised it to 8), and bad water quality. Lesson learnt, listen to people's advice as they have been there, done that.

[daniella3d]

If you are paying for your water, then you might want to consider a RO unit that is low on water usage like this one, which will waste no water, so cost much less at the end:

http://www.costco.ca/Premier-Zro-Pur...100016456.html

If you are using tap water I would start with using RO. This is probably your problem.

Originally Posted by ChizerBunoi

I am going to buy a RODI unit from BRS. Just looking at the cost of RO in my city, it's going to be $40 just to do a 40 gallon water change. That's not including the ATO water of 15 gallons a week.

Also going to try some BRS GFO in a media bag, in my filter sock. But I'll put it on the output of my protein skimmer.

I really want to get a way from carbon dosing entirely. It's scaring me off.

I am thinking it was a combination of ALK ( initially at 7 and then I slowly raised it to 8), and bad water quality. Lesson learnt, listen to people's advice as they have been there, done that.

Thanks for the link Daniella. That was the main reason why I didn't purchase a RODI in the first place. It just wastes so much water. I'll check out that unit you posted.