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Skimmer? Algae or Cyano?

762 Views 3 Replies 4 Participants Last post by  moonlitsomernite
Hi everybody. Been pretty busy in recent weeks/months and havent had much time for anything reefrelated except maintaining status quo. I trust that everybody is doing well.

For those who dont know....90 gal aga reef with variety of happy looking corals, stars, hermits, fish, rock, supported by power compact lighting, bioball sump, carbon pellet bed on top of filter pad. About 6-7 months old, no crashes so far.


1. Absent any residency/water/other changes inside the tank or apparatus, what might be the reason(s) for my venturi protein skimmer dragging butt so much? It used to be excruciatingly delicate to get the airflow just right to prevent overflowing volcano action, but now, even with the valve set to wide open the foam barely makes it up the column of the collector cup, and we're only getting about 12oz every week. I've cleaned the collector cup and the column inside the sump and that seems to help for about 12 hours. I have a hard time believing that my water is so crystal clean/clear that there isnt any scum to collect. I've tried blowing into the venturi valve, and while I blow the foam leaps right up and overflows like in the old days. Ideas?

2. I confess, I'm about 10 days behind on water changing (I was out of town and left family to (over)feed the tank)...and I see that my heretofore strikingly beautiful purple and burgundy coralline algae has faded tremendously. Some of it seems to be turning bright orange, too. Other coralline that was in the sandbed along the glass has turned dark brown (died and become cyano?), and so too has a little bit of it on one of the rocks. Normal cycling? Obviously I fear that the lag in water change hasnt been good, and I forgot to mention that up until about a month ago I had been a devoted user of Coral Vital liquid additive. Ideas and such that I should be considering?

Since my return yesterday the chems are ammonia and nitrite zero, ph 8.0 (already corrected today), nitrates 65+ (yikes!). Calcium, specgravity, and temperature fine. We use RO distilled water mixed with Red Sea salt beginning about one month ago (last water change) but before that used Tropical Marin.

Thanks in advance to everyone who takes time to respond...
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1. I had a similar situation with my skimmer. What I found was one large grain of my coarse sand subtrate had found its way into the intake of the skimmer and had lodged itself in the intake where it tapers down, just before the opening for the air intake. This cut the flow of the water at this point and limmitted the ammount of air intake. the air hole wasn't blocked at all, so when I blew into it, it seemed to work fine. I had to take the whole thing apart to find it, but when I put it back together, it worked great.

2. Nitrates bad!!! You need to keep up with water changes but I doubt that nitrates are your problem. You noted that you made two major changes recently. You stopped using a certain supplement and you changed your salt. I don't put much faith in supplements so I don't believe that they would be your downfall either. I would think that the change in salt is your culprit. To you and I, Salt is Salt. But to a reef, even minor differences are a big deal. A while back, I switched from Intant Ocean to Ocianic Salt and my tank did not like it at all. I stuck it out and my tank looks good now, but it was a scary couple of weeks when I changed over. The only other thing I could think of would be a temp. spike which isn't totally out of the question with recent weather.
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