Restarting old Tank... Opinions Please?

[Grits]

Hi, first off I'm new here. I have something I would like some experienced opinions on.

I'll give my tank specs first and then tell my situation.

My Tank:

75 Gallon Fresh Water
2 Whisper 60 gallon Power Filters
Under Gravel Filter
2 Maxi-Jet 1000's

My Fish:

1 Red Tail Shark
1 Rainbow Shark
1 Zebra Botia
2 Clown Loaches
2 Golden Rams
1 Black Swordtail
2 Common Plecs
3 Cories

My Plants:

A little Elodea and cobomba(not much)
1 fairly large Amazon Sword
1 Hygrophlia
2 smaller plants (I"m not sure of the name)

My Water:

pH - 7 (tap is 7.2)
KH - (4 DKH) (tap is 6 DKH)
GH - N/A
Nitrate - 40 (tap is 0)
Nitrite - N/A
Amonia - 0
Temp - 78-80 always

My Situation:

I've had this 75 gallon tank about 10 years. Most of the time there was a red-tail shark and yo-yo loach. They got really big and lived for about 8 years. But most of that time I wasn't living at home. My cousin was taking care of the tank for me.

I just moved back in and the tank was empty except for the 2 plecs. So one day I went by the fish store and left with the sharks and clowns. I kept checking the ph and ammonia and they were always PH 7.2 and ammonia 0.
So I thought everything was fine and got the other fish too.

Little did I know my cousin had NEVER done a water change. He would just wait for the water level to go down then add some more. He NEVER took any out for 7 or 8 years. So, I went out and bought a Nitrate and KH test kit, but the store didn't have Nitrite and GH. I'll get those soon as I can.

Anyway... How much harm could not doing the water changes have caused. And are those water parameters ok, or do I need to seriously work on anything?

Thanks in Advance!!!

 

[Zagz]

Welcome to AA!

Start with small water changes. Extreme differences from bad water quality to good water quality can shock the fish and make their systems weak. You will have to work to slowly get nitrates to below 40 ppm, 20 ppm or lower is better. Ph is best left alone and stable.

Make sure you use a good dechlorinator like Prime. Once the fish have acclimated to better water, water changes of 50% a week would be a good idea.

 

[mattrox]

Your plants could be taking care of the nitrates it seems. 40 isn't off the scale for nitates. Gravel vac small sections at a time to remove gunk would be what I would do. Say change 10%-20% of the water twice a week for 3 or 4 weeks with the gravel vac until you have removed the accumulated gunk.... then re test. Thats what I would do.... but there may be others who have other advice?