Replacing test tubes

**crystalite** · 06-22-2012, 04:21 PM

Should I replace API test tubes every now and again and if so how often? Also do I need to clean them in some way and if so how as at the minute I just rinse them under cold tap water but I'm not sure if there's traces of the chemicals left in them which will alter the results next time there used?

**Surfdog** · 06-22-2012, 04:47 PM

I replace mine when the very last vestiges of the measuring line fade away. As to trace residue, I follow instructions and clean as specified, nothing more.

**crystalite** · 06-23-2012, 06:55 PM

The 5ml line is still really clear but I can't find anything that says how to clean them in the instructions. I just seem to keep getting the same nitrate readings no matter which tank I test or how many water changes I do so I was almost hoping it was residue in the tubes.

**Lady Hobbs** · 06-23-2012, 06:56 PM

You just rinse them out a couple time in tap water. No need to change them out ever.

**Goes to 11!** · 06-23-2012, 08:25 PM

Originally Posted by Lady Hobbs

You just rinse them out a couple time in tap water. No need to change them out ever.

+1 This is what I do and have had no issues.

Originally Posted by crystalite

I just seem to keep getting the same nitrate readings no matter which tank I test or how many water changes I do so I was almost hoping it was residue in the tubes.

What is the reading you get? Also, Have you checked your tap water for trates?

**pjaldave** · 06-23-2012, 11:09 PM

Nitrates.... They are really hard to distinguish in API kits. 10 and 20ppm are almost (if not) identical.

And no, you never should need to replace your test tubes, unless it breaks on you.

**crystalite** · 07-11-2012, 04:23 PM

Thanks for the help guys. I've started drying out all the tubes when I've used them and my results have improved since. I think I had water left over in the bottom of the tubes that was stagnating and causing the high nitrate readings.

**Lady Hobbs** · 07-11-2012, 05:49 PM

I rinse mine and throw them in a box I used for all my testing stuff. If anything, a person could use a q-tip I suppose but I see no need for it. I'd be afraid of breaking them if I dried them. They are very thin glass.

**Goes to 11!** · 07-11-2012, 05:52 PM

Originally Posted by crystalite

Thanks for the help guys. I've started drying out all the tubes when I've used them and my results have improved since. I think I had water left over in the bottom of the tubes that was stagnating and causing the high nitrate readings.

Letting them air dry upside down eliminates this, It works for me.