Tank crashed for the second time

[Rhyno8]

I've had my mangrove Jack's tank running for four months now. Checked water before weekly water change on the weekend ammonia was off the chart nitrite off the charts. It happened about two months ago full mini cycle after a water change. I thought maybe that was a freak incident but now it's happened again.
It's a 75 Gallon with two canisters 2000lh jebao a 1200 lh aqua one both loaded with matrix and cintered glass media. I also just added two sponge filters with k1 to see if they'll help.
I add half a cup of marine salt for every ten gallons could this be messing the water chemistry up? The gh is about 500 and pH is 8

Tap water is soft pH of about 6.5 and gh of about 40.

Any help is much appreciated

 

[Aqualoon]

Have you checked your tap for ammonia and nitrites recently?

 

[Rhyno8]

Yeah did straight away 0 and 0 I can't figure so frustrating.

 

[Fish Tank Travis]

I know this is obvious, but I have to ask, are you using a dechlorinator when doing your water changes?

 

[Rhyno8]

Yeah, always use dechlorinator the waters mixed to temp in a bucket dechlorinator then salt added

 

[A-Train]

Have you vacuumed your gravel/sand? Any food left over in the tank? Or is the tank empty? try to buy Prime it does an amazing job and it is really strong it's a red bottle and fixes the problem within 2 days I had a similar problem in my 55 gallon but once I bought Prime never had it again also have you checked the date on your water test kit? If it expired it can just be reading your water levels wrong

 

[skjl47]

I add half a cup of marine salt for every ten gallons

Hello; At 1/2 cup per ten gallons that's 3 1/2 cups total for 70 gallons. Is this a freshwater tank?
As someone who never adds any salt to my freshwater tanks, may I ask why the salt??

 

[duanes]

The tank has been set up for a total of 4 months? From scratch?
It had a crash at 2 months?
Is this what you're saying?
All media in the filters is new, and uncycled ? (as old as the set up)
More media doesn't necessarily do anything, unless it is already seasoned
If so,
I believe the tank was probably not truly cycled yet
it probably wasn't properly cycled at 2 months.
How big is the Jack? A 75 is quite a small tank for a jack unless it is a juvie, especially if the tank isn't really cycled.
I can see adding salt, because i would consider the jack a brackish water fish,
and I doubt that would threaten the cycle, unless the salinity is drastically different from water change to water change.

 

[skjl47]

I can see adding salt, because i would consider the jack a brackish water fish,
and I doubt that would threaten the cycle, unless the salinity is drastically different from water change to water change.

Hello; Very useful post. This should explain the salt. I am not familiar with a jack.

All media in the filters is new, and uncycled ? (as old as the set up)
More media doesn't necessarily do anything, unless it is already seasoned
If so,
I believe the tank was probably not truly cycled yet
it probably wasn't properly cycled at 2 months.

hello; This make sense also. Good job of summarizing the conditions.

 

[duanes]

Where I live in Panama, they are everywhere, and called Pargo (red, or grey snapper) and as juvies are found in brackish water, in mangrove swamps but move to total salt (ocean) water as adults. They will sometimes swim up stream in rivers, giving the impression they also live in fresh water, but only temporarily.

I probably eat at least 1 or 2 each week, great barbecued in banana leaves, and cooked, but cold, the meat makes a great pate .