Phosphate vs Nitrate depletion

[Randy Holmes-Farley]

with todays equipment and how much bacteria is in our tanks i would cut back on the water change i do 50 percent water change every 3 months just to replace whatever elements i cant test for. the water i take out goes in my frag tank not a single issue been doing it for years.

FWIW, water changes do not always accomplish much in the way of phosphate export.

If levels are high, even a 100% change may not drop phosphate much after re-equilibration of phosphate off of rock and sand surfaces.

If levels are low (say, .01 ppm), it is not exporting anything significant relative to the large inputs every day from foods. If phosphate is too low, there's no clear way to attribute causality to water changes.

 

[AJsReef]

I had the same issues zero NO3 & PO4 & eventually ended up getting Dino's. Also lost a couple of corals because of no nutrients over several months. I was doing 2.5gal auto water change per night. I started using Loudwolf sodium nitrate & trisodium phosphate per http://theplantedtank.co.uk/calculator.htm. Made minor additions slowly with both of these. Checked both levels every day for a month. After the first week had levels to NO3 .03-.05 & PO4 .03-.6. Would check twice a day the first week or so because the levels would drop in the morning, not always to zero but in the low range. I also stopped the auto water changes during this time. Fed heavy twice a day LRS fish frenzy.
After a month of doing this (I also vacuumed the sand twice a day with a 1 micro sock to remove the dinos). Dino's are gone, corals have never looked better, great growth, color & PE. My levels are NO3 .10-.25 & PO4 .05-.10 & holding with in the range. I started the auto water changes back up after about 30 days of holding the range now 2 gal per night. Tank is 225 display w/40 gal sump.
Hope this help. I still test PO4 every day & NO3 every other & will for a couple of months. I don't want to deal w/ dino's again. Reagents are inexpensive vs lost corals.
FYI my tank is now 1 year old. Problems started 8 months in.

Hope this helps! Good luck.

Seems like a similar experience with what I had when I first set up the tank. Definitely thinking dosing PO4/NO3 is the way forward, just taking it the slow and steady approach. Test kits aren't the cheapest and the time spent is a wash but looks like I'll be doing it for awhile moving forward.

Debating on value turning off the AWC with such a small overall daily percentage though, don't want to change too many variables at once. Definitely don't mind dosing NO3/PO4 if it means I can have a stable routine.

Thanks for sharing

 

[GillMeister]

these tanks that are reading constant 0 what kind of equipment are you running in the sump. are you dosing vodka or the such to drive it down. frequent water changes. when my tank runs absolute zero its always bacteria driven.

I have chaeto in my sump along with a Bubble Magus D9 skimmer. I run carbon as well though I'm sure this isn't having a huge impact on the N and P. One potential factor is the 250 lbs of rock in my tank. It used to be speculated that anaerobic bacteria deep in the rock convert nitrate but I don't know if it’s been proven.

My water changes aren't frequent or large and I don't dose vodka.

 

[GillMeister]

I would also like to add that I feed a lot, and my fishes are CHONKS. I mean they are fat and sassy. Something is consuming nitrates very efficiently.

 

[blasterman]

My own theory on this, and I have nothing to prove it other than an educated hunch is that phosphate or nitrate consuming micro organisms become dominant but due to competition it's not probable both become dominant.

This would explain why you are typically fighting one and can't dose enough for the life of you or feed enough but not the other.

 

[Aqua Man]

I’ve increased this dosage to slowly to 20ml daily and still haven’t seen an increase beyond 0 on the Hanna ULR checker.

Not surprised. Took 10ml(Neophos) in my 20gl to get a reading, testing an hr later. Then at 24 hrs, the .026ppm back to zero! What does surprise me is how fast our systems use po4.

Any update? Did you Have better progress with the DIY solution?

 

[Thaxxx]

I saw your build thread. Very nice.
I may be mistaken but I didn't see many fish in comparison to the amount of corals you have. If this is the case, maybe increasing your fish population would go a long way in keeping higher nutrient levels. Also have you tried taking the cup off your skimmer, just using it for aeration? And if you have a refugium, taking out whatever your using in it. It would be interesting to see if there are any changes if doing those few things.

 

[AJsReef]

Not surprised. Took 10ml(Neophos) in my 20gl to get a reading, testing an hr later. Then at 24 hrs, the .026ppm back to zero! What does surprise me is how fast our systems use po4.

Any update? Did you Have better progress with the DIY solution?

I’m actually up to dosing 35ml day PO4 / 20 ml Nitrate which keeps me at .05/5ppm (I dose 50ml of Phyto which I’m sure helps here too)

I did purchase the Loudwolf Phosphate but haven’t ran out of NeoPhos yet

 

[AJsReef]

I saw your build thread. Very nice.
I may be mistaken but I didn't see many fish in comparison to the amount of corals you have. If this is the case, maybe increasing your fish population would go a long way in keeping higher nutrient levels. Also have you tried taking the cup off your skimmer, just using it for aeration? And if you have a refugium, taking out whatever your using in it. It would be interesting to see if there are any changes if doing those few things.

Fair point with the fish, I’m slowly building up the count. However, I’m really hesitant to add new fish since they are so established. Most I’ve had for nearly 10 years. Currently working with Ocean Devotion LA to pre QT fish. I’m adding 3 over the next few weeks and will be adding more every so often until I get it stocked heavier

I don’t run a fuge (haven’t in a few years) largely due to the ULNS situation. My skimmer is set to pull minimal skim. Maybe 1/4 a cup over a week. Even with that, it will bottom out nutrients in a matter of 24-36 hours without dosing from .05/5 where it’s at

 

[Nano sapiens]

I have been running a 12g nano for nearly 13 years without any mech or chem filtration (just weekly 10%/wk WCs). In all that time 99.9% of my PO4 testing has been 'undetectable' (Salifert/RedSea). I've seen just a very few times where I can barely get a PO4 reading which included having up to 7 small fish in the system or two adult Ocellaris Clownfish fed daily. NO3 has varied widely, largely based on the type and amount of food added (largely influenced by the number of fish present). I had Triton perform an ICP-OES test to determine organic phosphate, and both inorganic and organic forms together showed up at ~1/2 their recommended minimum amount. Per established reef keeping norms, I should have had pasty sick looking corals with little to no growth, but the exact opposite was true at the time of the test.

When sustained '0' PO4 test results occur in mature aquaria with healthy and vibrant coral, it seems to me most likely that a large population of bacteria are present and utilizing it. Since corals feed on bacteria, this would be a major source of phosphate for them. My system is predominantly driven by bacteria as I have very little algae growth (I don't even have any snails other than a few tiny Collunistas). I'm not sure if certain bacteria are better at taking up phosphate than others, but what seems most likely is that when one has a bacteria population that resides in the water column, it means more available phosphate for the corals when the bacteria are consumed. Interestingly, a AquaBiomics report showed that I have predominantly Pelagibacter bacteria which, as the name suggests, live free in the water column.

If this is indeed correct, this is a process of phosphate uptake that doesn't manifest itself in a way that we can directly see or measure with a test kit.

 

[AJsReef]

Don’t disagree, with adequate input that 0 PO4 isn’t necessarily a bad indicator. The difference in case examples here is your stocking in a 12 gallon creates a high input scenario. My case would be probably “low” stocking as I work to increase. Lack of input, is probably the root cause for my issues; poor growth, coloration, Dinos etc. Which can be solved with N/P dosing to an extent. From prior negative experiences, I don’t want to see 0s in either test lol.

 

[Nano sapiens]

Don’t disagree, with adequate input that 0 PO4 isn’t necessarily a bad indicator. The difference in case examples here is your stocking in a 12 gallon creates a high input scenario. My case would be probably “low” stocking as I work to increase. Lack of input, is probably the root cause for my issues; poor growth, coloration, Dinos etc. Which can be solved with N/P dosing to an extent. From prior negative experiences, I don’t want to see 0s in either test lol.

I do understand where you are coming from, though, as it usually takes a lot more time to fill up a larger aquarium and I'd likely strive to keep low, but testable levels at least until the system is mature.

 

[Randy Holmes-Farley]

Based on Nitrate results would it be relatively safe to assume a ratio (10:1) NO3 PO4. Meaning I should attempt to dose >.05ppm/day of PO4 in order to have detectable levels of phosphate?

No. There are many standard processes that reduce one and not the other, such as denitrification reducing nitrate or phosphate absorbing onto calcium carbonate surfaces, reducing phosphate. phosphate.

 

[jasper9]

I have been running a 12g nano for nearly 13 years without any mech or chem filtration (just weekly 10%/wk WCs). In all that time 99.9% of my PO4 testing has been 'undetectable' (Salifert/RedSea). I've seen just a very few times where I can barely get a PO4 reading which included having up to 7 small fish in the system or two adult Ocellaris Clownfish fed daily. NO3 has varied widely, largely based on the type and amount of food added (largely influenced by the number of fish present). I had Triton perform an ICP-OES test to determine organic phosphate, and both inorganic and organic forms together showed up at ~1/2 their recommended minimum amount. Per established reef keeping norms, I should have had pasty sick looking corals with little to no growth, but the exact opposite was true at the time of the test.

When sustained '0' PO4 test results occur in mature aquaria with healthy and vibrant coral, it seems to me most likely that a large population of bacteria are present and utilizing it. Since corals feed on bacteria, this would be a major source of phosphate for them. My system is predominantly driven by bacteria as I have very little algae growth (I don't even have any snails other than a few tiny Collunistas). I'm not sure if certain bacteria are better at taking up phosphate than others, but what seems most likely is that when one has a bacteria population that resides in the water column, it means more available phosphate for the corals when the bacteria are consumed. Interestingly, a AquaBiomics report showed that I have predominantly Pelagibacter bacteria which, as the name suggests, live free in the water column.

If this is indeed correct, this is a process of phosphate uptake that doesn't manifest itself in a way that we can directly see or measure with a test kit.

My AquaBiomics results show diverse bacteria but in a strange balance. One type I am missing that their results show as typical is Pelagibacter (which is how I found your reply mentioning it when I searched). If you think back to what if any bacteria you added, do you know what kind(s) you used?

 

[Nano sapiens]

My AquaBiomics results show diverse bacteria but in a strange balance. One type I am missing that their results show as typical is Pelagibacter (which is how I found your reply mentioning it when I searched). If you think back to what if any bacteria you added, do you know what kind(s) you used?

Most of the live rock is ~23 years old from an earlier 55g (most likely Indo or Fiji rock).

Three things stand out in my mind. One is real live rock from the reef. The lack of any filtration that could possibly effect the water column bacterial community. Red Sea salt which is partial produced from real ocean salt (has been shown to include viable ocean bacteria)