New reef tank issue (no sump, no skimmer)

[ovicez2004]

Hello. I have a reef tank in place for 3 months and I have a small issue: I do water changes every week, but after 4 days of thriving, my corals retract and only survive in the last 3 days before the next water change, and so on...
I mentione that all may water parameters are ok-ish. Nitrate - not detectable, PO4 not detectable, pH 8.
I have 2 pavona, 1 kenya tree, 1 xenia, 1 green star polyp, 1 discosoma. 20 gallon tank, external filtration (canister with Purigen, Matrix and sponges). No fish, only 2 snails... I feed corals 2/week and Aquaforest Power Elixir 2/week. I don't measure dKH... maybe that's the problem...

 

[fishski13]

With these corals dkh is not important as they are all softies and leathers. They tend to do better is slightly higher nutrients. When you say your phosphate and nitrate are not detectable what do you mean? They are reading 0? Or the test kit you are using is not reading them?

 

[ovicez2004]

My test kit did not read them I have JBL Po4 sensitive andJBL NO3... I ordered today salifert,I understand that JBL is not reliable...

 

[Crustaceon]

Keep in mind the primary reason why we do water changes is to reduce excess nutrients. I say "excess" because our tanks need some degree of nutrients in them. This is typically between 5-20ppm nitrates and detectable - .1ppm phosphates for most tanks. SPS tanks tend to run on the lower end and softie tanks like yours tend to run on the higher end. That being said, your issue is most likely water changes while having undetectable nitrates and phosphates. Another thing to consider is the size of your water changes and the temperature/salinity of the water you're replacing. I wouldn't do more than 10% water change ONLY IF NEEDED when nitrates in particular go above let's say 10ppm as a starting point. And always make sure the water you put back in is close to the same temperature/salinity as the tank temperature. This will keep you from shocking your corals.

 

[ovicez2004]

Thank you for your reply. That's the thing: after I do a water change, everything goes well for 3-4 days, after that no... when I test the water all values are the same... I don't understand...

 

[ovicez2004]

Is it possible to strip the water of all the nutrients by overfiltration?

 

[Koh23]

Jbl po4 test is, what i call - very reliable.

Comparing to hanna HI713 checker, results are identical, of course, within comparing written number and looking at colors.

If jbl dont change color, that dont mean po4 is 0, it mean that po4 is somewhere in range from 0-0.02.

And that is exactly what checker says, it can be 0.01 or 0.02, really dont matter. Confirmed in several occasion, with several water samples.

Of course, checker pinpoint value to number, jbl gives range approximation, but, end result is in margin or error, or with totaly irrelevant difference.

At least in all of my testing.

Salifert, on other hand had reputation of worst po4 test, maybe things has changed, but, again, in comparation to jbl and hana.... Useless....

No3 test are all the same, again, in margin of error, so...

But all of this dont mean that u have 0 no3, it simply mean that this is concentration in water, again, not representig true matter of things, no3 can be bound to algae, etc....

 

[ovicez2004]

Jbl po4 test is, what i call - very reliable.

Comparing to hanna HI713 checker, results are identical, of course, within comparing written number and looking at colors.

If jbl dont change color, that dont mean po4 is 0, it mean that po4 is somewhere in range from 0-0.02.

And that is exactly what checker says, it can be 0.01 or 0.02, really dont matter. Confirmed in several occasion, with several water samples.

Of course, checker pinpoint value to number, jbl gives range approximation, but, end result is in margin or error, or with totaly irrelevant difference.

At least in all of my testing.

Nice to hear that. Everybody recomends Hanna, and in Romania there are quite expensive...

 

[Koh23]

Same here, long ago, had salifert, didnt trust him, get jbl, again, didnt trust results, so i got hana checker....

After seeing trough some time that jbl and hanna results are nearly the same... Sold hana....

Now - jbl... I'd like to try af po4 test, but, dont have hana anymore, and dont have plan to buy it (also too expensive), so..... I stick to jbl....

 

[ovicez2004]

Update: I bought Salifert NO3 test, and I had 25-30 so that was the issue. I installed a Ketho refuggium and everything is ok now. Does anybody knows what ist this bubble on blue pavona?