Testing accuracy after water change?

  1. k9z3boys Member Member

    Did a water change - 20g on a 60g tank- last night about 9p. At what point will it be accurate to do test it? keeping in mind that the ammonia may not be accurate due to the prime dosing. I'm mostly concerned with the nitrites -- ammonia too but its trickier.
    anyway- i thought i read to wait 24h after but i dont remember where i read that or why....

    hope this makes sense....its rediculously early
     
  2. Lucy Moderator Moderator Member

    Hi k9z3boys
    I'd say 24 hours is a good guideline.

    Testing too quickly would simply reflect the new water not how quickly the bacteria converts the toxins.
     

  3. slade Member Member

    Waiting 24 hours will give you a good indication of how much effect your PWC had on levels. Testing an hour prior to the PWC will show how long it takes for levels to increase.
    These two readings will let you determine amount of water to change and length of time between changes.
     
  4. k9z3boys Member Member

    thank you for explaining that. makes perfect sense now.
    I will test tonight at 9- 9:30p
     

  5. virusmk Well Known Member Member

    If using prime it is safe and acurate to test eright away as prime do not remove ,but detoxifies amonia, nitrates and nitrites. So when you do test after wc using prime you sill get acurate results as if amonia nitrites and nitrates are present they will show up on tests. As anomia is detoxified still is present in to the water but present as not harmfull as free amonia.
    poeticinjustices not long ago created tread about this issue and she might be able to post the link here about all discussion there where a lot of mistery has been cleared
     
  6. k9z3boys Member Member

    so the test I did at 6a is accurate?
    I hope poeticinjustice does chime in now...solving mystery would be good!
     
  7. poeticinjustices Well Known Member Member

    LOL well I COULD post the thread if you really want it, but apparently it wasn't all that mysterious after all and it's a reeaaaaaaaaallllllllllllyyyyyyyyy wordy thread, even by my standards haha.

    Basically, the gist was that Prime should not affect the testings in terms of its mechanism for action. I spoke with SeaChem about this and what I got from it is that, if you are using a salicylate reagent test kit (API kits), then it's always going to read total ammonia - ammonia that is both free and toxic and ammonia that is bound up as ionized ammonium and therefore less toxic.

    However, I wouldn't test RIGHT after a water change simply because I'd want to give the water time to be well-mixed. I've tested both before and a couple hours after a water change on a tank that I knew had ammonia in it and I didn't get any surprising numbers. It was .5ppm before the water change, I did a 50% change, and the reading was .25ppm a couple hours after. No funny business. And what I got from my communication with SeaChem is that, provided the water is well-mixed, the readings will not be impacted by Prime when using a salicylate reagent test kit. It's just that the readings are always going to show total ammonia and will not differentiate between what is bound and what isn't.

    Anyway, that's the way I understood it. There's a weird comment on the SeaChem FAQ where the tech says that, with salicylate kits, you have to take the reading right away or it'll look like there's more ammonia in the tank than there is. I still don't understand why it says that because the email I got from SeaChem says something totally different.

    ANYWAY - I'll post the link to the thread for you, just have to dig it up, and let you decide for yourself. Just be advised, it's long, I type a lot haha. Sorry.

    EDIT: Here it is. Read at your own risk :p

    https://www.fishlore.com/fishforum/aquarium-water/173516-communication-seachem.html
     

  8. k9z3boys Member Member

    I understand the ammonia part, and we have spoken with seachem about this. that one I actually understand. we use the alert disc for more accuracy.
    this morning I did test the nitrItes and it read zero...before it was.... ummm...well not zero... between .5 and 1.0ppm.
    I only tested the nitrites this morning,...is it safe to say accurate test results? changed 9ish pm and tested 6a ish or is that the one that is more critical at 24h?

    I hope I am making sense. thank you for your patience.

    didn't know fish keeping meant being a jr chemist!!
     
  9. poeticinjustices Well Known Member Member

    Assuming the water is well mixed, Seachem said that test results for nitrite or nitrate should never be affected by Prime.

    Sent from my SCH-I545 using Fish Lore Aquarium Fish Forum mobile app
     
  10. k9z3boys Member Member

    right.
    last test results were nitrite 0
    ammonia... not accurate at probably 1
    nitrate between 5 and 10