High Phosphate

[BKyler]

I've been testing the Phosphates in my 55 gallon freshwater aquarium for the past 3 to 4 weeks and they are at 10. I've been using PhosGuard and changing it out every four days and the Phosphate reading will not go below 10. I've done water changes and still nothing. I tested my tap water and it's fine. I don't know if it's the food I'm feeding the fish. Any suggestions would be greatly appreciated.

 

[Aiken Drum]

Thats somewhere in the region of being 10 to 20x higher than it should be. What led you to start testing for phosphate?

Whats the phosphate test result for your tapwater?

Have you tested immediately before and after a water change? Do you see any drop in the test result and then it gradually rises again or does a water change make no immediate difference?

What is your water change schedule? How much, how often?

What fish do you have? How many?

What food are you feeding.

Are you overfeeding?

I know they are independant of each other, but what is your nitrate at?

Are you dosing any fertiliser for plants? If so, what are you using?

 

[BKyler]

I test for all the parameters and everything is where it should be except for Phosphates. I've always tested for Phosphates when I'm doing the water testing.

When I tested the tap water today for Phosphates it was normal.

I've tested Phosphates before and after a water change and it stays the same - 10.

I've been doing water changes about every two weeks. Usually about 25%.

We have two African dwarf frogs, one red tail shark, a pleco, two angel fish and two other fish (don't remember what they are).

I'm feeding the African dwarf frogs in the tank - Aquatic frog and tadpole food every day or every other day.

I'm feeding the Pleco - An Algae wafer every other day.

I'm feeding the other fish a pinch of Tetra Min tropical flakes every day.

Nitrate reading is normal.

No plants in the aquarium.

 

[Aiken Drum]

Phosphate isnt something that most people would be testing for. If you arent seeing any issues in the health of your fish and frogs then its probably nothing to worry about.

"Normal" doesnt tell me anything. I have no idea what you consider normal. Actual numbers.

If your phosphate is at 10 immediately before and after a water change, the phosphate is much higher than 10. I presume the max your test kit can read is 10? To bring it down you should change more water. A 50% water change should halve the phosphate if your tap water has zero phosphate.

Frogs and plecos are very messy and 25% water change every 2 weeks isnt really very much. It will only be bringing your water parameters down by 25% every 2 weeks. Your fish/ frogs are producing more waste in those 2 weeks than the 25% water change is removing so it just builds up over time. Try doing 25% water changes every day for a week and see if that brings the Phosphate down. Or even 50% per day. If that has the desired result then going forward you should be doing bigger, more frequent water changes if you want to control phosphate.

 

[BKyler]

When I say normal I mean the phosphate level in our tap water is at 0 to 0.25. I'll try the 25% water change every day for a week to see if that makes a difference.

Also, what about the food that I'm feeding. I read somewhere that some fish food can cause phosphate levels to rise in aquariums.

 

[Andy Sager]

Assuming your tap water's "Normal" reading is 0 or under 5ppm, then your phosphate is coming from the decaying matter in your tank whether it's from the fish feces or uneaten food or decaying plant matter, etc. Many flake foods contain phosphates so you need to read the labels to see just how much is in the products you are using. In the past, Tetra Min, formerly the industry standard food, had a lot of it in their foods. That may have changed over the years so you'd need to check.
I read that you are using Phosguard with limited success so here's another suggestion: Poly-Bio-Marine makes a product called the Poly Filter ( POLY-BIO-MARINE, Inc. ) This is a filter pad that removes a lot of things out of the water, from ammonia to some nitrates, medications, metals, most anything organic, phosphates, your mother-in-law , the neighbor's cat , etc. But seriously, I started using this product in tanks back when it first came on the market in the 1970s and it made a marked difference in the health of my aquariums. You can read the review of this product by FAMA ( Freshwater and Marine Aquarium) magazine here: POLY-BIO-MARINE, Inc.
It comes in 2 sizes ( 4"x 8" pad or 12" x12" cut to size pad) and when used in HOB filters or canister filters, you place this pad as the last thing the water goes through before it goes back into the tank. This pad plus good tank hygiene ( siphoning water from the bottom of the aquarium to get any detritus pockets out of the aquarium) may be your answer to keeping your phosphate levels down if water changes alone are not getting it done.

 

[Aiken Drum]

All fish food will increase phosphate, either through uneaten food decomposing or passing through the fishes digestive system. Your water changes will remove it. Some food will be higher phosphate creaters than others i suppose, but im looking at the nutrition values on a few common fish food types and they are all similar %s for phosphorus. Around 1%. Different products may contain more "crude ash" and therefore be higher in phosphorus. If your food doesnt specifically list phosporus you could compare the amount of crude ash listed with different brands of similar food. Lower crude ash should be lower phosphorus.

From the information given though, the smoking gun is small, infrequent water changes. Lets see if some frequent changes bring it down first. If it does, then does a weekly 50% change keep it there? If this doesn't help, then look at other things. You might try testing whatever makes up your aquascape in a bucket of water overnight to see if it raises phosphate. Ive heard of some artificial decorations leaching nitrate, so its possible similar might happen with phosphate.

Whats the nitrate test result?

 

[BKyler]

When you say place the Poly Filter pad as the last thing the water goes through before it goes back into the tank where does that exactly go? We have a Tidal 75 filter and in the filter basket it is: foam filter, polishing pad, matrix bio media and then the Phos Guard. So where would the Poly Filter pad go?

Also, any suggestions on a good quality fish food that would be low in phosphorous.

I'll test the nitrates tomorrow.

 

[Andy Sager]

When you say place the Poly Filter pad as the last thing the water goes through before it goes back into the tank where does that exactly go? We have a Tidal 75 filter and in the filter basket it is: foam filter, polishing pad, matrix bio media and then the Phos Guard. So where would the Poly Filter pad go?

Also, any suggestions on a good quality fish food that would be low in phosphorous.

I'll test the nitrates tomorrow.

You'll notice that your water comes up from the bottom of the filter to overflow into the tank so you would place the poly filter pad on the top of all your other media so the water will go through all your other media then the poly filter then back into the tank. This way, the Poly filter will remove what your other material didn't. Depending on how much space you are taking up with your other media, you may need to weigh down the poyfilter so that it doesn't float out of the filter. If you use the cut to fit pad, I'd cut it to size but leave long enough tabs on the pad so that they go down the inside of your filter and be held in place by your other media.
As for foods, there are too many on the market these days and new ones coming all the time so you need to check what you have available. I know Dr Bassleer has good foods, Northfin, Omega One as well but I'm sure my list is very incomplete. In my hatcheries I use more frozen and live foods than flakes so I've lost touch on what is out there.

 

[BKyler]

Nitrates are 10 ppm. I checked the Tetra Fish flakes that I'm using and on the back it says <1% phosphorous.

 

[Aiken Drum]

Like i said. The issue is more likely to be small, infrequent water changes. There is phosphate in all fish food, and they are pretty consistent at around 1%. Cheaper fish food with more filler (crude ash) will be higher, but its not going to cause off the charts phosphate on its own.

Lets say your phosphate is 10ppm after your water change. Its probably higher, but lets go with that number. And lets say your phosphate goes up by 2ppm a week. So after 2 weeks, your phosphate is at 14ppm. A 25% water change reduces it by 25%, so after your water change your water change its now 10.5ppm. Another 2 weeks your phosphate rises to 14.5, and the 25% water change brings it down to about 11ppm. Over time your phosphate creeps up and establishes at a high level.

Lets run the numbers on a more frequent, bigger water change schedule. Start with the same 10ppm phosphate level, and the same 2ppm rise per week. But this time we do weekly 50% water changes. After a week, before your water change your phosphate is 12ppm. 50% water change and the phosphate halves to 6ppm. Another week goes by and your phosphate is now 8ppm before your water change. 50% water change and the phosphate halves again to 4ppm. Over time your phosphate lowers and establishes at a lower level.

If your water change schedule isnt sufficient to keep water parameters in check at a safe level you either need less fish (less waste), bigger more frequent water changes, or a bigger aquarium (more dilution). Or as most people do, if your parameters arent causing issues, just live with it. Most people wouldnt be routinely testing phosphate levels unless they are observing an issue and trying to diagnose a cause. Ive no idea what the phosphate level is in any of my aquariums, but i do frequently change 50 to 75% of the water and have no reason to believe the parameters are elevated.

Id give the different phosphate absorbing media @Andy Sager suggests too. Maybe that will chemically resolve the issue, but really 25% water change every 2 weeks isnt very much.

 

[Andy Sager]

Nitrates are 10 ppm. I checked the Tetra Fish flakes that I'm using and on the back it says <1% phosphorous.

Good. They must have changed the formula. As I said, it's been a while.

 

[BKyler]

Took the PhosGuard out of the filter all together and not putting it back in. Not going to test for Phosphates anymore. I did a 50% water change yesterday and this morning two of the fish are hiding behind the filter now and don't seem to be acting right. They never did that before and I haven't seen the two Dwarf African frogs at all. Hopefully I didn't take out too much water.

 

[Andy Sager]

Took the PhosGuard out of the filter all together and not putting it back in. Not going to test for Phosphates anymore. I did a 50% water change yesterday and this morning two of the fish are hiding behind the filter now and don't seem to be acting right. They never did that before and I haven't seen the two Dwarf African frogs at all. Hopefully I didn't take out too much water.

The 50% may have been too much for those fish and hopefully they just need some time to adjust to the change. I would highly recommend using that Poly-Filter pad so that you can see, by the color the pad changes to, what is coming out of your water. Not checking your water is not necessarily the answer. The worst husbandry is blind husbandry. Not knowing what's going on will eventually bite you in the butt. It happens all the time, especially to the ones that say " I do this or that to my tank so nothing is going to happen to it. " In time, many long time aquarists can tell something is wrong just by the actions of their fish. Most aquarists however, don't see the subtle changes that are clues until the fish shows advanced symptoms which at that point, may be too far to recover from. So it's best to prevent things from happening vs trying to fix things after they happen and you've lost your fish.

 

[BKyler]

Just added the Poly-Filter pad. How long do I need to leave it in?

 

[Andy Sager]

Just added the Poly-Filter pad. How long do I need to leave it in?

It should stay in all the time and be replaced when it becomes very brown from the color change. The different colors the pads turn are explained here: Poly Filter Chemical Filter Media Pads: What YOU Need to Know

 

[BKyler]

Thanks!

 

[BKyler]

The Poly-Filter pad has been brown from the moment I put it in. That is the only color it has ever been.

 

[Andy Sager]

The Poly-Filter pad has been brown from the moment I put it in. That is the only color it has ever been.

That means you have a lot of organics in the water. Have you taken a phosphate reading to see if the level has reduced?
Also, this is from Poly biomarine regarding when to change the filter:
You can tell the POLY-FILTER is working by observing its color gradually changing from an off-white to a brown color after prolonged exposure to contaminants in your aquarium. Cut POLY-FILTER in half when dark brown in color. If cut cross-section is also dark brown replace with new one.

 

[BKyler]

I did a 25% water change yesterday and hardly sucked any food/material, etc. out of the tank. I just took a Phosphate reading it was off the charts high.