goin the wrong way

Could you test your new salt water that you have on hand for water changes?
alkalinity, calcium, and magnesium.
What make of test kits are you using?

 

sera

 

And do you have water you can test?
Also, specific gravity reading is necessary if you report on readings for the new salt water. Lower s.g. mixing means less calcium and magnesium.

 

i have ro water that has no salt in it should i test it or what till tomorrow to get ro water with salt in it

 

i put seachem adv. magnesuim in tonight so i hope it helps

 

I think most experienced hobbyists have a container of new salt water mixed on hand for water changes and for emergencies.
You should have a lot ready to go now if these problems persist.
While the water can be used soon after mixing, in a pinch, I believe it better to mix it up to the s.g. you want, and then aerate overnight before using.
If you have salt and also have the R.O., then I would mix it up now and aerate overnight before testing tomorrow.
What brand of salt do you use?
With readings like you report for magnesium, it would take way too much of the seachem to achieve proper results if your readings are correct, so I wouldn't bother at the moment.
See the mag portion of the chem calculator and see if your product is listed and then plug in the results you have and want. It is amazing how much product is needed to boost magnesium.
Reef Chemistry Calculator
It would be much better to use multiple water changes to at least start with the salt mix's inherent levels.
I don't have any experience with Sera kits, and I don't think they were included in the testing done by Randy Holmes-Farley.
Randy found Salifert to be the closest to reading calcium levels similar to results found by laboratory testing, with seachem next in line with results apparently about 50ppm lower than the lab results.
Many hobbyist test kits are not all that accurate for some testing and that includes testing for calcium and magnesium which can produce erroneous results very easily for someone inexperienced in the testing.

 

I dont understand how your Mag went from 1000 to 720 in a couple of days. For some reason, I think that test kit isnt giving you a correct reading. Before you do the WC, Go to your LFS and ask them to test your water. That way you'll know if its your tester or something else.

 

Oh yay! Another trip to something fishy

 

Testing the new salt water should provide the same answer. If his readings don't compare with most other hobbyists results for the same brand, then either the kits are defective or the procedure is somewhat incorrect.

 

I agree with you, but he doesnt have any salt water.