Lesson on stability

Just thought I'd post an update on my tank. I'm quite proud of my tank and corals. I get great growth and coloration. Everyone that has seen it has remarked about it. I don't get the polyp extenstion I'd like on my SPS, but hey - I guess I shouldn't get too excited if I don't have everything......


As everyone that knows me also knows that I'm a stickler for detail and consistency. I do regular water changes - I seldom miss a weekly change (unless I'm on vacation). But its only a 5% change - and still I have good water chemistry. Nitrates and phosphates almost 0, calcium 420; alkalinity - 8.0........


So you can imagine my surprise recently with two items:


1) Water chemistry test. The water test came back with all good numbers on the basic parameters (potassium quite low and couple things). BUT, salinity was only 1.023. I really thought I was running the tank at 1.026 (at least according to my refractometer). But, I haven't calibrated it in I guess what has been a long time. So don't know how long my salinity has been that low - or when it started going low. Anyway lucky for me that although I was off, the tank wasn't lower than 1.023 - which is the lower end of the recommended range. And I guess its a good testimony for the importance of consistency - that that is more important than the 'exact' number.


2) I got a new RKL. Bought it at Thanksgiving time, but only got around to installing it last week on my cube tank. 1st thing I noticed was that the temperature was reading lower than I thought the temp to be in the cube tank. So I moved it to my display tank, which also has a RKL unit attached. So, I have 2 temperature probes and 2 RKL head units. Between the old head unit and temp probe and new head unit and new probe, I have a 2 degree variance. My DT is set for a temp of 77.5. The new unit with new temp probe reads 75.5. So which is right???? Bud offerered to loan me his Hanna PH/TDS checker with temperature. I got it this afternoon. It reads dead on with the new temp probe/head unit. So, if its correct, then the new temp prob/head unit is correct - and I've been running my DT at 75.5. Hmmmmm. Again - within the parameters, but just alot lower than what I had set for my target - and maybe why I have such a hard time keeping it at that temperature in the summertime. I wish I had another temperature source to use for checking, but probably don't have one.


So - my point here is that there is alot of truth in the advice that keeping your tank conditions stable is maybe more important than trying to hit a specific 'number'. At least for my case, this seems to prove out..


I'm planning to increase the salinity back up to 1.026 (gradually over a period of a week of so) and then to calibrate more frequently. Also, unless I come up with another way of getting an additional accurate temperature reading, I'll probably raise the DT by at least a degree - that would still leave it well within the acceptable range - while allowing additional room in case of an error.

 

Bud has loaned me his Hanna Combo checker which measures temperature. It seems like good quality and reliable. It measures almost exactly the same as the temperature probe on the new controller. Before I finalize on using that as my temperature, I was wondering if anyone else (in the Des Moines area) has a temperature guage that you are pleased with that might come and take one more reading for comparison. Thanks!!!

 

My temperature difference is due to both the probe and the controller. Calibration is not difficult to do. The challenge is finding a trusted source (or sources) to be used to make the calibration to.