# Does PH test solution expire?



## ojustaboo (4 Oct 2017)

Hi, I have a API multi test kit that's 7 years old, I also have an additional PH test kit that's about 5 years old.

I have 4dkh solution.

I had my CO2 on from 1pm until 7pm.

I initially had my drop checker on the side of the tank, using 4dkh and a few drops from my 5 year old kit.

It stayed blue, the colour didn't change..

I then moved it after 3 hours right into the flow of CO2 bubbles coming out the spraybar. It still stayed exactly the same shade of blue.

I've just done test tube tests on the tank water using both kits, both give the same result, between 7.0 and 7.2.  I also tried the high range  PH test, that goes from 7.4 to 8.8. The result was lighter than than the 7.4, which points to what the other two tests say, between 7.0 and 7.2.

I understand that I should concentrate on what the plants are doing, but the drop checker isn't changing in the slightest. I have a 180lt tank (about 40 gallons) for the first 4 hrs I had 2 bubbles a second and for the last 2 hrs I had 6 bubbles a second going in and with 6 bubbles, I could clearly see the CO2 reaching the bottom of the tank. 

But zero change in the dropchecker.

Part of me thinks maybe I should invest in a new PH kit, but part of me thinks the chances are the colour will more than likely be the same (do they actually go off?) , and if they do have a limited shelf life, how do I know they haven't been in my LFS or online store for a few years?


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## Zeus. (4 Oct 2017)

Test kits waste of time and money. lots of threads about them.The Drop checker kits shelf life isnt great once opened. Buffers vary on temp and other factors. Mine lasted about 9 months. Haven't bothered to get any more.

I picked up a pH pen recently *Semlos 0.01 Resolution Digital PH Meter Large LCD Pen Water Quality Tester* £14 to check my pH controler probe. Very happy with it easy to calibrate. Great way to see you pH drop instantly. 

 pH pen it before CO2 on then various time of day, instant no wait see the drop. Cheaper than pH controller, which I just use to test the pH nowadays, have a button I press and displays pH for 15mins, use pH pen to check if probe is starting to fail.

If someone was to ask me about a pH controler I would say they are good, but dont bother, just get a pH Pen.


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## PARAGUAY (5 Oct 2017)

On the API the expiry date is on the label on individual bottles and on the instruction card should be date of manafacture eg a kit from 2007 could have expiry of 2017. For drop checker use I use the Aqua Essentials Bromo


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## ojustaboo (5 Oct 2017)

Thanks. I might get one of the pens.

Today I took 4 test tubes, midday, 2pm, 4pm and 6pm (CO2 comes on at 1pm to 7pm)

midday and 2pm were the same colour blue. I turned my  co2 up slightly, 4pm and 6pm were getting towards green, very obviously more green than the first two.

Maybe I need more CO2. I'm at about 8 bubbles a second at the moment.


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## ojustaboo (7 Oct 2017)

I upped the bubble count a bit, hard to count in a second now.

Things are a lot better, bubbles getting to the bottom of the tank, drop checker showing a drop from 7.5 before CO2 to 6.5  two hrs after CO2 went on. Also checked at 4 hrs and it had gone down to 6.4

Fish seem happy so don't think I'm putting too much in.


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