Phosphate bottoms out daily

[WrasseMan89]

I've run into a little bit of a problem. About 3 weeks ago my nutrients bottomed out and I got the oh so fun dinos. After UV, blackout, and manual removal I am on the downhill slide. Now I find myself in another situation, I test nitrate and phosphate daily right now and nitrate usually comes out about 6 maybe 8ppm. Phosphate however always bottoms out and comes back 0. I dose Neophos to bring it up to .03 or .04 but even if I test again that night it's back to 0. I'm not heavily stocked, it's a 35g with a small watchman goby, maxima clam, and about 4 euphyllia. I tested my parameters yesterday and everything came back OK.

Salinity 35
Magnesium 1275
Alkalinity 9
Nitrate 6
Phosphate 0 - dosed neophos (.03)
Calcium 440

My tanks about 4 months old and I did use dry rock but I've always had some phosphate so I'm not sure what happened. I do dose MB7 and my phyto and pods come today so I will add that as well. Do I just have to dose phosphate multiple times a day until it levels out?

 

[Randy Holmes-Farley]

Feed more or dose food grade sodium phosphate.

if dosing, one need not dose multiple times a day. Once a day so that at least 0.03 ppm is present 24 h later is sufficient.

 

[Weaverjay101]

The only two thing I can think of are that the new bacteria growth are consuming the phosphates or that the dry rock is absorbing it. Try upping the dose and see what happens.

 

[Dragen Fiend]

4 months was my breaking point for stabilizing my 15G tank. Went from cyano to dinos in a matter of a couple weeks after lowering nitrates/phos. I now have a stable 10 nitrate and 0.04 phos.

I found it had everything to do with what I was feeding and how many times I was feeding.

Instead of dosing neophos have you looked up switching your foods with higher phos content? As well as just feeding more. Increasing nitrates to 10 will likely get you higher and more stable/detectable phos.

 

[Randy Holmes-Farley]

. I dose Neophos to bring it up to .03 or .04 but even if I test again that night it's back to 0. I'm not heavily stocked, it's a 35g with a small watchman goby, maxima clam, and about 4 euphyllia. I tested my parameters yesterday and everything came back OK.

There's no reason to not run out the Neophos before switching to something else (that is less expensive and has a purity guarantee), but for now, dose a LOT more each time.

It's not unusual to have to dose a very large amount when first trying to bring phosphate off of zero due to the large amount of each dose (or feeding) that will bind to rock and sand.

 

[WrasseMan89]

Feed more or dose food grade sodium phosphate.

if dosing, one need not dose multiple times a day. Once a day so that at least 0.03 ppm is present 24 h later is sufficient.

Thanks! When I was figuring out how to combat my dinos I did see your info about the food grade stuff, I will try to feed more frequently and if I need to continue to dose I will get the good stuff.

 

[WrasseMan89]

4 months was my breaking point for stabilizing my 15G tank. Went from cyano to dinos in a matter of a couple weeks after lowering nitrates/phos. I now have a stable 10 nitrate and 0.04 phos.

I found it had everything to do with what I was feeding and how many times I was feeding.

Instead of dosing neophos have you looked up switching your foods with higher phos content? As well as just feeding more. Increasing nitrates to 10 will likely get you higher and more stable/detectable phos.

Thanks! I'm going to increase feeding and see if that helps. I will throw in some pellet foods since I normally only use mysis.

 

[nereefpat]

What specific phosphate kit are you using?

Are you carbon dosing or running GFO?

 

[Timfish]

Sponges and biofilms are messing with PO4 along with everything else in your system. Some cryptic sponges in aquariums can sequester phosphorus in the form of polyphosphate crystals. Depending on the biology of your system quite a lot of phosphorus can be removed. Or conversely, put back out to the water column. Since these processes are dynamic you'll need to monitor things and add or remove as needed. As your systems matures (~8-12 months) things will balance out and testing and dosing may be less frequently needed. Feeding your fsih is the best way to raise PO4 as the urea and ammonia are also corals preferred forms of nitrogen.

FWIW .03 mg/l minimum threshold level identified by Southampton University in England. Since they determined it by looking at phosphorus deficiency in corals maintained in aquaria for up to around a decade seems like a definitive lower number until we can quantify particulate and dissolved organic P used by corals. Upwelling can expose to corals to .3 mg/l so that seems like a fine number for an upper limit for an aquarium. However, Dunn, et al showed increased growth with moderate levels of .5 mg/l. At the higher end the sexually reproduced corals at the Steinhart Aquarium are being grown out with .9 mg/l PO4 and 50 mg/l Nitrate.

Here's a video by Rich Ross, one of the researchers at the Steinhart Aquarium.

 

[forneyjohn19]

When my tank was first started my phosphates were also always at 0.0. Started my tank with dry rock. I would also dose neophos, and 24 hours later be back at 0.0. Five months in I started dosing neophos on an auto doser. Finally, four months later I measured steady phosphate levels (without needing to dose neophos) and stopped dosing neophos.

I am by no means an expert, but have read that dry rock may bind phosphates. My experience would support that claim. Your current situation sounds similar, and will require patience. Find a way to get phosphorous in the tank. I have a nano tank, so neophos wasn’t that expensive and an auto doser was easy for me.

Keep fighting the good fight! Things will get better!

 

[sharkbait-uhaha]

I was currently at 0 phosphate and low nitrates as well for a while and decided to feed reef roids as everyone always said that it raises phosphate .
After 2 feedings ( once a week ) and every other day water change I now have some detectable phosphates

Phosphates 0.0ppm /nitrate 1.2ppm - before
Phosphates 0.09ppm/nitrate 10.1ppm - now

 

[Salty_Northerner]

It's been a year this month since I got this WB set up and to this day I still get my up's n down's of phosphate. When I started I had Dino's for what seemed forever. Anyways long story short, I'd dose neophos at Brightwells recommend dose and that didn't do it. Sure I'd get detectable reading but by next day they back to zero. So I'd add double the dose and the system would hold detectable numbers by the following day and it took some time getting phosphate up and to get the Dino's away. But it worked and a year in I still have low days but my plan of attack is reefroids and or neophos/ Tropic Marin plus-NP and my average now is .076

I'll sometimes broadcast feed or spot feed the roids and come next day the phosphorus will be in the 40's ppb so I'm happy with that. As my system is maturing I'm finding different ways to keep the phosphate up without polluting the water. Example, a few days before a WC I'll reefroid the tank. If after a WC and the numbers are below .05 I'll dose plus-np as I know the corals response is positive and also the detectable nitrate drops very slowly and my glass box shows as I don't need to scrape it so often.