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FAQs on Marine Water Quality involving Phosphates, Science

Related Articles: Phosphates in Marine Aquarium Systems by Marco Lichtenberger, Phosphates in Carbon; An analysis of the phosphate content of activated Carbon by Steven Pro, Ammonia, Nitrates, Nitrites, SilicatesMarine Chemical Filtrants,

Related FAQs: Phosphates 1, Phosphates 2, & FAQs on Phosphate: Importance, Measure, Sources, Control, Chemical Filtrants, Troubleshooting/Fixing, & Nitrates, NitritesAmmonia, Silicates, Avoiding Algae Problems in Marine System, Nutrient Control and Export, Algae Control, Marine Maintenance, AlkalinityChemical Filtrants

Understand what you're doing before trying to "do it"...

Stubborn Nitrites... Another case of zip [HPO4]       5/8/17
Hello Crew! Thank you for all of the advice over the years. Your site has been an invaluable resource.
<Ah, good>
I'm having a problem with stubbornly high Nitrites after (during?) a cycle for a quarantine tank and I'm out of ideas.
<Well; quarantine systems tend to be unstable, disallowing establishment and ready metabolism of beneficial microbe populations... Do you have sufficient biomedia, circulation about it to sponsor nitrification?>
QT is 20g, HOB BioWheel filter with bagged carbon and GFO (there was a Phosphate issue from uncured dry rock in the display tank).
<Is there still "some" soluble phosphate present? You NEED some for microbial conversion of Nitrite to Nitrate... Re-read that last statement>
Also has a small skimmer as I intend to follow the mantra "Quarantine everything, corals and all" with this new display tank (150g). QT is bare bottom except for some pieces of pvc for hiding spots and tests at 0 Ammonia, 20 Nitrates, 2 Nitrites, 0 Po4,
<Bingo: Here's at least part of the problem. Remove most/all of the GFO>

480Ca, 9dkh, and 1250mg.
We use water from the display tank for water changes (was an attempt to seed, but also a way of acclimating the critters to heir eventual conditions. Currently the only inhabitants are 3 Scarlet Reef hermits.
Nitrates are coming down (artificially high from early on when the both tanks were showing 100+ Nitrates.... DT now shows zero after water changes and a little impatient Vinegar dosing).
<Won't help>
What is NOT moving however are the Nitrites. They've been floating between 2-3 for weeks. The QT has been running for almost 2 months and they just won't come down. I've tried everything. I've even added SeaChem stability to the area behind the Filter wheel in an effort to directly add <sic, aid?> the bacteria necessary. It just won't come down (but isn't going up either). We are doing water changes, but only @10% weekly. I know that a
bare bottom tank takes longer to cycle, but this just seems absurd. I would have expected a spike and then drop over a longer time. Not a constant 2-3ppm with no movement. The kit is Salifert, brand new, and tests fine at 0ppm on the DT as well. I'm completely out of ideas. Any thoughts? I know Nitrites are not as bad for marine organisms, but I'm not relishing the thought of subjecting a really cool frag to Nitrites just because I can't get this thing to fully cycle.
<Your situation is very commonly misunderstood. "Some" phosphate is absolutely necessary to all life... part of DNA, RNA, Phospholipids in every cell... ADP, ATP energy transfer molecules... AND conversion of NO2 to NO3... The (over) use of chemical filtrants has killed more livestock than pathogenic disease. Remove the rust and you will find your nitrite gone in short order>
Thanks again!!
<Glad to help Frank. Bob Fenner>

Phosphate question   3/10/06 Hi all.  I have been reading about phosphates at wetwebmedia.com.  One of the suggested ways to reduce phosphates is to :  "Raising pH like with Kalkwasser... to 8.4-8.5 to precipitate out the phosphates for good." <Can be employed, yes> Now, I have very high phosphates (off scale with Salifert test kit) but I wanted to test your suggestion.  I took a water sample (about 40 mL), starting pH was 8.15 and added 1 drop of 1.0 M NaOH. <I would not use sodium hydroxide (except to clean dirty ovens)> the pH raised to about 8.75.  Maybe there were a couple of small crystals formed, but no major precipitation.  I tested the water and the phosphates are at about the same level.  I them lowered the pH back to 8.08 by adding 0.02 M HCl, retested and got the same results. Questions: 1) Have you done this and have it work in a tank? <Have not used the chemicals listed... well, have used Hydrochloric in other applications. The reference refers to Kalk...> 2) What is the insoluble phosphate species that is supposed to form? <Calcium phosphate [Ca3(PO4)2].> 3) Wouldn't this be a reversible process? <All processes are reversible... but the energetics, chemical species in a marine aquarium discount this> 4) Is the precipitation supposed to be a slow process (i.e. hours?) <Nope... almost instantaneous> Thanks for your time. R., Romero <Please try the Kalk, Calcium Hydroxide... Bob Fenner>

Re: Phosphate question Thank you  - 03/11/2006 I was trying to do the experiments with reagents I have prepared in the lab.  I will prepare some saturated Kalk and try to repeat this.  In the interest of science, I may try it next time I also do a water change on the 'old' water, before I attempt the live tank.  Thanks for your time Romulo <Welcome. Bob Fenner>

Phosguard and SPS coral  - 5/18/2006 Hey everyone, <Hello Marc> Just a question about some information I received from a local LFS. The guy told me that the continued use of Phosguard (by SeaChem) will slow the rate of growth of my SPS corals. Have you heard this before or had any experience with it and have you found any other 'chemical' absorption media or the like that can be an issue with corals??? <Marc, the SeaChem Phosguard is aluminum based and extended use can release potentially toxic aluminum into your tank.  There are phosphate removing products that are not aluminum based and safe to use.  One such product is ROWA phos.> Thanks <You're welcome.  James (Salty Dog)> Marc RO I have high phosphate in my tap water--0.1ppm--so I bought a GE brand reverse osmosis unit. This RO water still contains about the same amount of phosphate, so I installed a Kent post DI canister. The water output after the DI still contains 0.1ppm of phosphate according to my test kit. Any thoughts? <although such water purifiers do not guarantee to remove all inorganic/organic phosphate... do consider that your colorimetric test kit is unable to read below .1ppm accurately. Such hobby grade kits really are poor quality. Still useful though. Have you tried to test the effluent of your RO (the reject water) to confirm that a higher level of phosphate exists there? It should... else more reason to suspect the test kit is inaccurate or unable to read. Do try other test kits for comparison. Kindly, Anthony>

Phosphate Blues... I recently moved to small rural community in Indiana, into a temporary rental house with corn and soybean fields surrounding it. Not surprisingly, after (Early-Oct) I set-up a small (30g) reef tank with our well water, I began to have algae problems of a magnitude never experienced living in the  San Diego and Denver areas. Initially, I had tested well-water for NH4/NO2/NO3 with no significant result. Today I finally received PO test kit, full-scale 10ppm with well/+5ppm with "city water" available in town. No wonder my 20% weekly water changes were ineffective. Yikes! Yep, all you were doing with those water changes was re-supplying the algae with food!> I am using a TetraTec 300 and Eheim 2213 with lots of Carbon, also a Prism hang-on (OK, I didn't read up much before tank set-up), and undergravels with sweeper heads ( Ditto, should I ditch the undergravel & powerheads?) <I am not a fan of undergravel filters in most situations> 20lbs of good Fiji LR, just 4 small Damsels, 4 medium hermits. Can I use a remote holding tank (Rubbermaid 22G) and economically remove phosphate from water using Poly Filter (12.00ea) in a small hang-on? <Polyfilters can remove quite a bit of phosphate from source water. I love them! However, I think that you'll need to take more aggressive means to eliminate it for the long run...> My alternative is =1.00$ per gallon DI or distilled from the local drinking service at $1.00 gal. Randy R. <Well, in the long run, I'd recommend an R/O unit for purifying your makeup water  source. I realize that it's expensive, but when you consider that Polyfilters need to be replaced after they are exhausted (which varies, depending on how much they are able to absorb in a given period of time), the R/O is the better way to go in the long run, IMO. Yep- the initial cost is greater, but over time I think it will pay for itself.> P.S. I don't want to waste your resources on more important questions, I can contact the manufacturer, but I thought you might be able to give me an expedient answer. <Please don't hesitate to contact us if you need assistance, okay? Regards, Scott F.>

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