First, I'd like to offer a huge thanx to Vince for hours of work this weekend. Last Friday, the main circulation pump (Pan World) stopped moving water though the pump was still alive. I told them to unplug it until I could get there. mysteriously, the next morning, the pump was working fine. This Friday, the zoo called again and reported the same thing. This time it wouldn't restart and it was apparent that something was binding the impeller which meant disconnecting the pump and opening up the housing. Vince was kind enough to meet me at the zoo Sat. morning. Due to a design oversiight, we forgot to plumb in a ball valve between the sump drain and the panworld which meant that Vince and I had to drain the whole sump to remove the pump. We figured we might as well clean out the sump and all its contents while we had it drained since their was a lot of crud and calcified scale build up. We had to re-silicone the drain bulkhead and let it sit overnight. We let the impeller and housing parts sit in vinegar over night to get all the calcified crud out that was apparently freezing up the impeller. Our fear was that the pump might have burned out from the frozen impeller. So this morning we put everything back together, put in a ball valve, refilled the sump and voila....it ran like a top! So now we have a clean sump, skimmer etc. It appears that external pumps are not maintenance free so we will have to clean the impeller about every 5-six months. Next time will be much easier since we wont have to drain the sump!
We also tested the magnesium and found that it was only about 1040 which could help explain the excessive build up of calcification, as well as difficulty maintaining alk and Ca levels. I started boosting the Mg and it is now at about 1120. I will slowly raise it to about 1300. If anybody has a Mg test kit and could verify my readings please let me know. I used a salifert kit but I don't always trust Salifert readings.
Finally, we tested the PAR in the tank and it was woefully low. Surface readings were barely above 100 and par was around 70 along the bottom. This, as well as the Mg problem as well as Ca/alk instability can all help explain our sps failures. Vince will contact a reefer in Portugal who has established himself as a t-5 maven to consult on proper lamp configuration for our system. We were thinking of swapping out two actinics for 14k lamps. We'll see.
I also placed a bunch of mexican Turbos in the tank and they are doing their job. Algae on the live rock is rapidly dissapearing and cyano on the sand bed is receeding since we imposed a daily one hour lights out interval.
So all in all, we are slowly tweaking the system and working out the kinks. It is my hope that by the spring we can sart succesfully adding sps frags.
Oh and BTW, if anybody needs anything from "The Filter guys" I will be placing an order for ro/di replacement filters this week.
