Neptune Optical Sensor brown gunk in ATO clean SW bucket with reef crystals

[bknope]

For the last two months my “low saltwater” optical sensor has been getting brown/red gunk or spots, causing it to think it is CLOSED when it is not, causing my DOS to think there is still clean saltwater to put in the tank.

I use reef crystals mixed to 1.026.

Now, I’ve ordered a new sensor (just in case the sensor magnet is causing this) and will be cleaning the bucket, but does anyone have experience with this?

I’ve heard of reef crystals leaving brown residue but how is it settling on the optical sensor?

I could get a powerhead to keep it stirring but then it would need a spot on my apex so it gets turned off when the water is too low. It’s also weird this is a more recent problem

Thoughts?

 

[AJsReef]

For the last two months my “low saltwater” optical sensor has been getting brown/red gunk or spots, causing it to think it is CLOSED when it is not, causing my DOS to think there is still clean saltwater to put in the tank.

I use reef crystals mixed to 1.026.

Now, I’ve ordered a new sensor (just in case the sensor magnet is causing this) and will be cleaning the bucket, but does anyone have experience with this?

I’ve heard of reef crystals leaving brown residue but how is it settling on the optical sensor?

I could get a powerhead to keep it stirring but then it would need a spot on my apex so it gets turned off when the water is too low. It’s also weird this is a more recent problem

Thoughts?

I was never a fan of the residual reside from Reef Crystals. Are you intentionally targeting high parameters? If not, Red Sea Blue or Tropic Marin Pro mix much cleaner.
If you go the power head route just test placement and add a defer statement for when it’s truly open and not just water movement triggering

 

[NanoDJS]

They add ferrous oxide to that mix .....

 

[bknope]

I cleaned out the bucket (first time in over a year maybe...) and it had a layer of ferrous oxide.

I’m going to monitor it as I would rather not change my salt yet as my anemones and corals seem happy at the moment.

Maybe I need to clean the bucket more often...

Thanks all

 

[ca1ore]

I cannot speak to the residue specifically, but I would not rely solely on the optical sensor. I have a few in my system and I do not use them to control anything, just send alerts. They foul very easily and then send a false positive.

 

[fishbulb]

I run one of the marineland micro filters in my saltwater bin just to clean that stuff up. It is frustrating.