Refractometer Issues

[01Buckeye]

Hello to all;

I have a question in regards to refractometers and how long they are generally good for. I have both a Sybon 100sa and a simple Coral Life Deep 6 swing arm type. I bought the Sybon in the past year so I could moniter a hypo-saline treatment for a fish, which the Deep 6 did not register at the low levels or read at smaller incraments. I've had the Deep 6 for 5+ years and use it primarily for testing the main tank and aging water change buckets. For my own amusement, while testing the display tank, I used both and found the Sybon gave me a reading of 1.025, while the Deep 6 measures around 1.021-1.022. In testing the Sybon with "ultra" pure water, I get a reading of 1.000, which, according to their users manual would say that it is calibrated properly. With the age of the Deep 6, could it be "off"? I have no idea how to check it's calibration. The reason I ask is that I am having some mushroom bleaching occur. Fish seem to be doing fine. I thought maybe the shrooms were reacting to a higher SG than they should be at. My other readings, taken just this afternoon are:

pH: 8.2, Temp: 79F, SG: see above, Ammonia: 0ppm, Nitrate: 0 ppm, Nitrite: 0ppm, KH: 8 deg, Alkalinity: 3.5 meq/L, Ca+: 380 mg/L, Phos: 0ppm

My other thought was that the Ca+ levels are a bit low, but didnt' think shrooms really used much Ca+. I also does with Essential Elements once a week between water changes. There are no other corals even close to touching the mushrooms. I have 4 (2 daylight x 2 actinic) compact flourescent bulbs that were replaced in July of this year.

Thanks for any help or suggestions.

[Reefing Madness]

Sybon Standard Seawater 35 ppt Calibration Solution - product summary - Bing Shopping
Have you checked with calibration solution?
Your swing arm style, being a Hydrometer, are not very accurate and iffy. You could take 5 readings and have them all different. You should rinse the Hydrometer out with fresh water after each use, so salt does not collect on the arm. Shrooms start to bleach out after you changed the lighing? How old was the lighting you changed? May be the shock of new light. CA should be 420ish, yours not terribly off. And the levels you have taken for SG, even if it was 1.022, your shrooms would not be in terrible trouble. I've been using the same Refractometer for, hmm, been over 8 years at least.

[01Buckeye]

The shrooms didn't go in until after the lights were changed, so they weren't exposed to my "old" lights. The Hydrometer does get rinsed in RO water after each use. I'll have to pick up some calibration solution to check the Sybon. The mushroom colony was added in late July and was doing great until the last week or so.

Thanks for the tips.