If you're on a regular water change schedule, do you test your parameters before or after WC or both?

[RichReef]

I am in a routine at this point so I only check right before a water change to know if I have to make adjustments to my daily dosing and I am still on track.

 

[jsker]

Before my auto water change.

 

[fyrefightr]

I have a 125 and do a WC every other week. I test phos, nitrates, mag, ca, and alk the morning of my WC just to see what has happened during the two weeks. I test Alk regularly throughout the two week period. I retest the morning after the water change to see what difference the wc made.

 

[99gtbaby]

Was just curious.

If you're checking before, it must be because there's some kind of issue. And then if you check after, it's to see if things need to be replenished.
But if you're on a regular WC, you change on a set day so I guess most people do after? Even though theoretically, changing the water should replenish your water with minerals?
I've ONLY been checking after, but I'm wondering if I benefit from checking before and after?

Someone educated my uneducated self, thank you.

Both, I test immediately before and then 24 hours after.

 

[Kate Vellis]

Do you test water before or after feeding AB+?

 

[Bruce Burnett]

If you are only changing 10-15 percent at a time unless you are way off on your parameters or temp it will make very minor changes to what is already in the tank. I just make sure salinity is at 1.026 and check nothing else in new batch.

 

[Mr. Mojo Rising]

I think you should do what makes you feel comfortable. i think we all go through a new tank phase where we test every day, or at least very frequently. As the tank matures and you feel more comfortable with the stability of your tank, you will test less and less often.

 

[Snoopy 67]

I change 15 gal./wk & test water from the tank then.
If a parameter is low I can add to the water going back in.

 

[GMF21]

Not sure it matters if you test before or after, just as long as you are consistent with your method.

Sometimes testing before, sometimes testing after will give results all over the place.

 

[mucky1957]

I do a water change at the end of each month and I do all my testing around lunchtime every Friday.

 

[Reef.]

I do mine after but unless you are doing say a 50% w/c then you are unlikely going to notice a difference, most tests are not that accurate to be able to register a 10-20% water change.

 

[olonmv]

I’m pretty bad about testing especially if I’m on a consistent wc regimen. I visually look at all livestock for abnormalities and test if something looks wrong. I usually change 3 gallons per week or every other week on a 13.5 evo.

 

[Emerson]

I think it depends on what parameter you’re testing. I test Alk almost daily, so if I tested the day or two before, I’m more interested in what I have after the water change. I also test for Ca and Mg after for the same reasons; not that I do those tests daily, but that I get more value knowing what those parameters are after I’ve replenished major/minor/trace elements through my monthly 20% water change. For NO3 & PO4 I’m interested in what the tank is doing on its own for nutrient export, independent of water changes. I’ll know those numbers are ~20% less after the water change.

 

[PeterB113]

I do both one day before and a few days after

 

[attiland]

If I'm mixing my water before I do my WC, I still need to check it? I always check salinity but I never check other parameters for my new water

I actually check alk as well as my tank running on a significantly higher alk than my salt mixes at. My salt is mixes at around 8.3 and the tank is about 9.3. I check so I can add alk accordingly.

 

[BradB]

My default routine is I test Alk weekly, change water monthly. More frequent changes, or different tests are only if I suspect a problem.

I avoid checking Alk a few days before my water change, and usually check 24-48 hours after. I don't completely trust any salt on the market, although almost all salt is probably good. I want to know where my Alk actually is and if my salt was off, rather than calculate what it will be assuming my salt is perfect. It doesn't hurt to check more often, and checking Ca after is probably a good idea too.

If Nitrates are a concern I'd check before a water change just so I'd know how much to change. I have no problem assuming Nitrate in my salt is 0.

Anything else measured, such as Phosphate, water changes are a poor idea to fix the issue. Of course, a lot of things, such as cyano can show up and tell me I need a water change that can't be measured.

 

[brelson]

Generally, checking before determines need for water change and checking after determines effectiveness of water change BUT you want to wait 12-24 hrs after water change to test again as there will be suspended matter giving false results. Water changes are a method to remove nutrients and replenish elements. In the beginning stages of your aquarium, it may be the only way elements are replaced.
If your tank is looking a bit dirty, or your corals are not as perky as usual, these are indications that a water change is needed. If you are having algae issues or test results are showing high nitrate, or phosphate, then you need to increase the volume and frequency of the water change.
When doing a water change, we have to consider the inhabitants of our tank. Make sure the temperature of the water you are adding, is the same as the tanks current temperature. The ideal temperature is anywhere between 75 – 80°F (23.5 – 26.5°C) .
Test the salinity of your new water so it matches your tank water. If you find your tank water has high salinity you may want to consider adding an auto top off unit to your tank. Make sure to match the salinity while aiming for 35ppt or 1.025 sg.

Great info

 

[rtparty]

None. I use a quality salt with a good track record or consistency