4 dead 2 more sick

[Lester]

Hi All Thanks in advance

Here's what I've got:

I checked on tank at 0800 4 pregnant platies are dead 2 don't look so good. The rest of the fish are at the service gulping for air. Snail even crawled out.

37 gallon tall with small sponge filter, 307 fluval with under gravel input and spray bar output. Gravel substrate 9 inches in the back 3 inches in the front with bags of fluval stratum aquasoil. Medium planting. Heavy stocked due to platies breeding. Lights on for 11 hours mounted 4 in over tank. No lid. 1 year old.

Coop test strip:

No chlorine I'm on a well.

Ph 6.4

Kh 40

Gh 300+

Nitrite 0

Nitrate 50 to 100

No ammonia 

Tds 850(not sure I believe this going to order a new meter)

What I've done recently(3days): 

I did a normal water change 25 percent.  I use rodi water. I reminiralize to 200 tds and aerate with sponge filter for at least 24 hours and heat. I trimmed a bunch of stems out. I added 40 blue dreams from another one of my tanks. 

I removed dead fish.

I'm happy to supply more info.

What should I do?

[Colu]

If your  nirates are closer to a 100ppm that can cause rapid breathing hanging near the surface listlessness effect your fish immune system can kill them also your pH is on the low side for platy they like a pH of 7- 8.0 and your KH is really low they like a KH above 170ppm it could be a combination of the low pH and KH coupled with the high nitrates I would add some crushed coral to your filter to raise your KH and pH and increase water changes to lower your nitrate add an extra air stone and a Small amount of aquarium salt 1 table for 5 gallons that will aid Gill function and add essential electrolytes @Lester

[Lester]

Wow thanks for the quick reply.  I do have crushed coral in water storage and filter. I will add an air stone and some salt. Will salt hurt the plants? I will perform a water change until nitrates lower. I will also clean filter in a couple days to increase water flow. Thanks again.  I'll let you know how it goes.  Do tanks lose oxygen over night?

[Theplatymaster]

platies need higher PH than 6.4

[Colu]

On 11/28/2022 at 7:21 PM, Lester said:

Wow thanks for the quick reply.  I do have crushed coral in water storage and filter. I will add an air stone and some salt. Will salt hurt the plants? I will perform a water change until nitrates lower. I will also clean filter in a couple days to increase water flow. Thanks again.  I'll let you know how it goes.  Do tanks lose oxygen over night?

Salt at that level shouldn't harm your plants just remember to only put back in the amount of salt you take out so if you do 5 gallon water change put 1 table spoon of salt back in I would leave the salt in for a week  as your using crushed coral and your still having a low pH and KH I would  double the amount of crushed coral your using to help gradually increase your pH and KH  in the short term you could add some wonder shell to help add some mineral back for your platys @Lester

Edited November 28, 2022 by Colu
Typo

[Lester]

Some how I made two post.  I put an update on the other one and I'm going to try to delete this one.  Thanks for your help.  I plan to lightly clean filter tomorrow and add more crushed coral.  I also did a test with api and got 7.4 to 7.6. I added a air stone. The Fish are doing much better. I thought this tank was on auto pilot.

On 11/28/2022 at 11:29 AM, Colu said:

Salt at that level shouldn't harm your plants just remember to only put back in the amount of salt you take out so if you do 5 gallon water change put 1 table spoon of salt back in I would leave the salt in for a week  as your using crushed coral and your still having a low pH and KH I would  double the amount of crushed coral your using to help gradually increase your pH and KH  in the short term you could add some wonder shell to help add some mineral back for your platys @Lester

 

[Colu]

On 11/29/2022 at 2:20 AM, Lester said:

Some how I made two post.  I put an update on the other one and I'm going to try to delete this one.  Thanks for your help.  I plan to lightly clean filter tomorrow and add more crushed coral.  I also did a test with api and got 7.4 to 7.6. I added a air stone. The Fish are doing much better. I thought this tank was on auto pilot.

 

If you pH is 7.4-7.6 then I wouldn't add extra crushed coral you could add some wonder shell to help raise your KH