Nitrate issues

[Lypress]

Hi guys! I have a 90 gallon tank that I’ve had for years and recently had issues keeping the nitrates at a lower level. Back in January I purchased a blood parrot, I took him back to the store I bought him at 2 days ago because he was so aggressive and was destroying my plants. about 3 weeks ago I purchased 3 clown loaches, one went off by itself, stopped eating and died. The other 2 were doing fine so I went back and bought 3 more for a total of 5. Again 1 went off by itself and died. Then almost a week later another one did the same thing and died. Now I have only 3 again but so far so good. I also have a dwarf gourami that was constantly hiding because of the parrot so I honestly don have a clue what her normal behavior should be. It’s my first time owning one. Now that the parrot is gone she’s swimming all over the place. Today I observed her swimming fast back and forth turning sharply and only going about a foot to a foot and a half and about every 3 seconds or so flicking her tail. No shuddering, just a single hard flick. I see no signs of disease so I wonder if she was angry or maybe the nitrates? When she stopped pacing and just swam normally about 20 minutes later she was no longer doing this. I have been doing 50% water changes weekly and changing the polishing pad weekly as well. 2 days ago I did my water change and polishing pad as usual then retested the nitrates the next day, they were still slightly over 20 ppm which I don’t want because I’m getting black algae again. So yesterday I did a 20% water change and changed the polishing pad again which was black with gunk again! Grrrr. So currently I have 1 common pleco about 6”, 3 clown loaches about 1 1/4”, 7 corys, 1 kuhli loach, one blue dwarf gourami so my tank is under stocked. I also don’t over feed and my lights are on high 8 hours a day. My readings this morning were:

ammonia: 0
nitrites: 0
nitrates: 20
phosphates: 1
temp: 78

this is after 2 water changes and the values don change much. I’m attaching these photos so you can see the setup. The plants are live not fake and growing rapidly. this was tank January 21, 2020this was taken a few minutes ago.Here’s my Gourami. Any help is appreciated.

 

[Wrench]

I'm not an expert and learning about stuff all the time so if I'm off I apologize but google can also help....ok, i have had a high nitrate number in my 28 gal. tank for awhile, i am a little overstocked unlike you but have read a bit.
#1 ,have you been cleaning the substrate?
That is where nitrates like to live and the plants feed off of it.judging by your growth from the pictures your plants are doing their job absorbing what they can.
#2,Phosphate, this is another by-product of uneaten and waste build up, this will create algae blooms and depletion in oxygen levels in the water,the plants will grow all over the place faster than you can trim them.
#3, sea chem,purigen pouch
Sea chem, phos guard..I think called,also in a pouch.
Get them both, rinse them off and put them in with your filter media.
The purigen will polish the water and will not let the nitrate levels exceed what they are right now.
The phosphate pouch will lower the phosphate level in the water and help it keep good oxygen content while not letting the plants take the tank over.
Get those.
Clean the substrate, I use a siphon hand pump I got at home depot,its gray,has a filter on the bottom of it, i put it all the way into my gravel and draw my water exchanges from there.
If it runs brown or milky looking you know you've gotten too the goodies helping the plants grow, your 90galls. ....I'd pull 50% of the water right from under the substrate,fill it up and check it the next day.
The purigen will male your water blindingly clear, with that and the water exchange you will see a decrease in nitrates and more so with every subsequent water exchange

 

[Lypress]

Hello wrench! Thank you for your response. I vacuum constantly when doing water changes and use a water changer. The phosphate right from my tap is 1 but with all the maintenance this is ridiculous lol. I am still growing the plants to fill in the right side to match the left. I need them to get tall to hide the fishing line I had to use to keep the plants in the arch shape due to the flow of the filter. Also with all the cleaning lately I haven’t cleaned the glass so the pictures make the water look bad but it is actually mostly clear. There aren’t as many plants as it looks. I’m keeping the back clear for open swimming. I took a few more pictures

 

[Wrench]

Sweet! , I just recently cleared the back of my 55 gallon as well, okie dokie.
My advice on the purigen still stands to keep your nitrates where they are now, and like i said they will lower each time you change the water from here on out until your at 0-5ppm.
I do not doubt at all your water is clear, the purigen will truly make it crystal.
I put it in both my 55 and 28 and actually watched it working in the 28 lol.
I was fascinated and sold on it at the same time,and for 9 bucks as a piece of mind knowing nitrates wont rise continuously is always nice.

 

[Lypress]

Sweet! , I just recently cleared the back of my 55 gallon as well, okie dokie.
My advice on the purigen still stands to keep your nitrates where they are now, and like i said they will lower each time you change the water from here on out until your at 0-5ppm.
I do not doubt at all your water is clear, the purigen will truly make it crystal.
I put it in both my 55 and 28 and actually watched it working in the 28 lol.
I was fascinated and sold on it at the same time,and for 9 bucks as a piece of mind knowing nitrates wont rise continuously is always nice.

Thanks! I will definitely try that!

 

[AvalancheDave]

20 ppm nitrates isn't going to hurt anything. Make sure you're not using any "liquid carbon" products or StressGuard as they contain a chemical used to poison fish.

 

[Lypress]

the only thing I use other than prime and a clarifier is flourish maybe once a week but I don’t think that will hurt them. could it be the blood parrot? He’s gone now, I sold him back to the last. He was pretty large. Today nitrates are down to 10 ppm so I’m happy with that. Do you know why I am getting black beard algae again? Could that be the phosphate? It is only 1 ppm?

 

[AvalancheDave]

Not Flourish Excel?

Clarifiers can cause problems. They're probably the same flocculants used to treat drinking water.

Their potential for toxicity is well known:

Google Scholar

Aquarium product manufacturers have a really poor track record borrowing chemicals from other industries. AlgaeFix and the Tetra knock off use a cooling tower biocide which has caused numerous tank wipeouts.

This hobby almost requires you to be your own toxicologist.

On top of being a chemist, pharmacologist, biologist, and microbiologist...