bluegill fingerlings in my first time setup are kicking off

[Stalemate]

My wife picked up 40 bluegill fingerlings and 4 catfish on friday to add to our first setup which we just finished cycling.  9 of them died on the way home, and 5 a day for the next two days.    The ph is reading 7, no amonia signs and water temp is 71 degrees.  Also,  a few fish are showing discolored regions on their back and tailfin.

Is this mortality rate in a stressful move usual? Should I be investigating / worrying about an underlying problem that may kill them all?  When I visit them, they seem happy. They are usually grouped on the  sunlight side of the tank and eat small coy & goldfish pellets that i'm crushing for them

[George]

Jon:  Do you happen to know the concentration of salt in seawater?  Too, at what concentration would you think salt becomes harmful to most vegetables?  Thanks.  I'm kicking around an idea of a brackish system.

Jon Parr said:

 I would salt the whole system to 5 ppt and hold it for a week or two. Most plants will stall during salting, but will regain growth when returned to fresh water.

[RupertofOZ]

Seawater is typically 32ppt...

Most plants can handle 5-6ppt of salt for several weeks... enough to deal with most disease issues... and system top-ups usually mean the salt is diluted... and along with some evaporation, and uptake by the plants... usually drops back to around 3ppt within a month...

Strawberries are sensitive to anything beyond 2ppt.... cucumbers, snow peas and some beans don't like much above 3ppt...

[George]

Thanks - I think that eliminates vegetables from any brackish water system - would probably need mangroves or something to remove nitrate.  At some point I'd like to try raising salt water bait minnows.  There may be a market for large minnows.

RupertofOZ said:

Seawater is typically 32ppt...

[Stalemate]

update:  The population of the tank stabilized since my last post.  The bluegill have all seemed grow at different rates over the past 4 months while the catfish all have grown significantly.

All of the fish are noticeably less stoked about food time lately.  I'm chocking this up to the fall temperature drops;  60 degree water in the mornings, heating up to 67 degrees in the day.

Which brings me to my next decision point as an owner;  I have not arrived at a water heating plan for the winter.  I have an unused 200watt submersible aquarium heater.  However,   I've seen some estimates that 400watt heater would be appropriate for a 300 gallon tank such as my own.   I'm wondering if there is anything short sighted about trying to make it thorugh the wither with the 200 watt heater?  I'm also considering creating a solar-heater pvc box and route the system through it over the winter.     I guess i'm looking for an economic middle ground between barely overwintering the system and introducing energy to have the system thrive through winter.

[TCLynx]

So you have to decide how important is it to keep the system growing through winter or would you be ok with simply keeping it alive and letting it sort of hibernate?

I will just caution that the solar heaters can backfire and be radiant chillers if you forget to turn off the flow through them or cover them at night.  Some sort of automated thermostat to control the flow through the solar would probably help there.

[Roger]

Thanks for all of the useful info everyone.  My fish are arriving tomorrow and they will be in transport for about 2 hours.  They will be delivered to my work place where I plan on providing them with an airstone for a few hours before I take them home.  Any other suggestions?  What type of salt are people using?

TCLynx said:

Just be careful with bluegill not to salt too high since they are supposed to tolerate salt levels above 5 ppt well.

Channel Catfish take salt even less well.  I don't salt over 3 ppt with the catfish normally.

But yes, I like to salt a system if I know I'm going to be handling the fish heavily or for transport or in a new system where stressed fish will be getting introduced.  Salt between 1-2 ppt is a good tonic to help with stress and slime coat.  3 ppt is appropriate for illness or injury.  Just make sure you have good aeration since adding salt will decrease the amount of oxygen the water will hold a little bit.

[Jon Parr]

Course rock salt, and/or potassium chloride, both available at HD in 50 lb bags for $5 and $15, respectively. If they look good when you get them, I'd leave the bag sealed up and forget the airstone. If sufficient O2 remains, it is probably better than messing with air.

[TCLynx]

If the fish are bagged with pure oxygen and not overstocked in the bag then Jon is probably right to say leave them sealed up.  Since if packaged properly fish will often be transported overnight so a single day in the bag shouldn't be too bad as long as you have stuff ready for them upon arrival home.

Be sure to float the bag in your system for 15-20 minute to let the temperature equalize.

When I get new fish I will often count them out of the bag into a salt bath at about 5 ppt with an air stone and then I transfer them into the fish tank.
  I avoid dumping the bag water into the system since that can be pretty foul.

[Stalemate]

Radiant chilling is something I had not thought about.  Does APsource sell any such switching products? My system uses 1/2" pvc.  I was thinking about building a 4' x 2' box and running black-painted pvc through to heat the water. My logic was to keep the box inside the greenhouse to preserve the energy.     Through some rabbit whole when looking up radiant chilling I came across PV as a superior technology for heating water; any thoughts?  

(I may respond to my own post with a series of lmgtfy.com links)

TCLynx said:

So you have to decide how important is it to keep the system growing through winter or would you be ok with simply keeping it alive and letting it sort of hibernate?

I will just caution that the solar heaters can backfire and be radiant chillers if you forget to turn off the flow through them or cover them at night.  Some sort of automated thermostat to control the flow through the solar would probably help there.

[TCLynx]

I don't know what thermostat type products AP source carries but you can buy thermostats that could turn a separate small pump on or off.

Instead of painting PVC black, I would say go get a coil of black polyethylene pipe to use, like irrigation or drinking water pipe, it is not that expensive.

[Jon Parr]

Stalemate, PV as in photovoltaic? I'm curious how that will be justified. It is well known that PV panels get as hot as hell, and become less efficient as they get hotter, so maybe someone has designed a water-cooled PV panel, netting both electricity and hot water.

If using the PV electricity to heat, I just don't see a remote chance of PV being remotely cost-efficient to heat water.

[Stalemate]

Appreciate the bluntenss on photovoltaics. I'm just chasing ghosts.  After digesting, I think the idea would be to have the PV panel directly drive some sort of submersible heating element. As you pointed out, 300W solar panel is not cheap. And i can't find any such 12v heater.

I inspected the 200w heater I have that I remember touting "fully submersible  (it looks like the ones for sale in the store here ). It has a do not submerge beyond this line text on it. Assuming I should  construct a raft If I want to use it in the system that will keep water level at appropriate line?

Jon Parr said:

Stalemate, PV as in photovoltaic? I'm curious how that will be justified. It is well known that PV panels get as hot as hell, and become less efficient as they get hotter, so maybe someone has designed a water-cooled PV panel, netting both electricity and hot water.

If using the PV electricity to heat, I just don't see a remote chance of PV being remotely cost-efficient to heat water.