Posting for someone. phosphates

IowaJeeping

New member
Is it common for new saltwater to contain phosphates?

I have been battling some uglies in my tank for a while. Thought i finally got rid of it, but alas it is back again. I have noticed that my phosphates do not seem to be affected much by waterchanges , while my nitrates on the other hand fall with every waterchange. I actually struggle to keep nitrates above 5ppm.

Today i decided to test a batch of red sea blue bucket that i mixed a few days ago, and my new water is mixing at 0.04 phosphates.

This makes a lot of sense as to why my phosphates do not seem affected by waterchanges. Is this normal or should phosphates be 0 in new water?

I have been aiming to keep the tank around 5ppm nitrates and 0.03 phosphates, bc i know that 0 can promote dino's.

I have noticed if i stop waterchanges, my sand bed clears up, and when i start waterchanges again, the stuff on the sand comes back.

I have had an icp test done in the past on both my tank water as well as my ro/di water. My ro/di water showed high silicates. I switched to the pro series resins, and added a booster pump to hopefully eliminate that issue. I did this several months ago and cleaned the storage tanks really well, as well as did a series of large water changes to remove silicates from the tank water. I have essentially changed around 210% of the water 30% at a time.

I have sent in samples for icp testing again and am waiting for the results, but i doubt i still have a silicate problem with my ro/di water. If i do, i have no idea how to fix that. Source water is 26 tds, 4 tds after the ro membrane, and 0 coming out of the resins.

Thoughts?

Update on some more info....

tank has never had excessive no3 or po4 from the start. I feed frozen mysis and reef roids. If i stop the reef roids and waterchanges, no3/po4 falls to 0. I know that 0 is bad, which is why i feed reef roids to keep no3/po4 above 0.

It's been a struggle for sure. I didnt test for no3/po4 for a long time and wondered why my colors were pale and my chaeto always died out. Upon research i found that pale colors could be caused by lack of nutrients. Tested no3/po4 and they were both 0. This was a while back, like 9 months probably. At that point i tried dosing them directly and corals responded negatively. I lost a few sps frags. So i started feeding reef roids to raise them. Now my chaeto grows good and my coral colors are 10x better. I have been aiming for no3: 5-10 po4: 0.03-0.04. Once no3/po4 started to rise slightly above 0, i started getting this stuff on the sand. I believe it is dino's. It doesnt look horrible now but I've been here before, it got much much worse last time. Research found that dinos thrive in a low nutrient tank, so i kept going with reef roids and raised no3/po4 to 15ppm no3 and 0.08 po4, and also stopped waterchanges as recommended by my research. After a few weeks at those levels, the sandbed cleared up, but i had gha everywhere.

I let that ride for a few weeks and then began manual removal of the gha, i did a 30% waterchange during gha removal. The spots on the sand bed came back, not terribly bad, but they were there.

I dose the tank with fluconazole to help kill gha that was down in the rocks that i could not get to, and stopped waterchanges for 4 weeks while the fluconazole did its job. Sandbed cleared up a few days later, and gha has almost completely disappeared. At this point i was feeding reef roids sparingly. No3 had fallen to around 8ppm, but phosphates were staying around 0.06.

After the fluconazole treatment, i did another 30% waterchange (instructions say to do large waterchange). No3 fell to about 4ppm, yet po4 has remained at 0.06. That is what prompted me to test the new water. I assumed if waterchanges were reducing no3 and not po4, then i must have po4 in the new water, and i was right. And now here we are, with an ugly sandbed yet again after a waterchange.

Parameters in the tank are:
1.025
79f
Ca 430
Alk 9
Mg 1400
No3 4
Po4 0.06
Ph 8.0-8.3 (according to apex probe)

I dose saturated kalk water every other hr throughout the day via a dosing pump.

Lights are hydra26hd's set to ab+ spectrum. 8hrs total on time with a 2hr ramp time.

This is from BRS ask Facebook group

Sent from my SM-N950U using Tapatalk
 
A couple of thoughts. No, there shouldn't be any phosphates in a reef salt mix. While I'd be as disappointed as you that there were any, realize that 0.03ppm phosphate is extremely low, and is definitely getting into the "insignificant" range.

From the standpoint of phosphate concentration in the water, 60 ppb phosphate (as opposed to 180 ppb phosphate - make sure that you're multiplying the Hanna ULR phosphorus test by 3) is really, really low. It's possible that this low of a result is due to algae up-take of nutrients, depending on how much algae you have in the tank.

As far as the sand, keep in mind that it'd be an extremely rare reef tank that had perfectly white sand. Generally those are the tanks run as ULNS by OCD aquarists, where the sand and rock appearance is more important than the health of the corals. ;)
 
My first thought is running some GFO, since that sometimes helps, and it's easy to do. 0.04 ppm phosphate is on the low end, and possibly running close to the detection limit.
 
Back
Top