Concerning the rates of evaporation being slightly different every day, more common is the rate changing slightly between day and night. The level drops slightly during the days and rises more during the night hours. The minor changes in humidity temp etc are not enough to significantly effect the water level as a day to day average. Any significant changes, especially in a temperature controlled dwelling like a home of office, will occur from season to season - not day to day. And the tank is never left long enough without a water change to make a difference. I used one of these pumps to dose a 2gal nano for a couple years and it would take at least two weeks for the water level to creep less than one centimeter either up or down. Because I was usually doing water changes more often than that, it was never anything I had to address.
I have settled on the rate of 0.32ml 8x's every minute and for three days it has been holding the water level in my sump at the exact water line mark I drew on my sump with a sharpie - just under the line in the evening, and just over the line in the morning. If it looks like there is a net gain or increase in the level at the end of the week, I will increase or decrease the dosing rate by one stroke per minute.
I wouldn't trust a float switch to do my topoff. Not saying there's anything wrong with it - I just think there is too much risk of it sticking on or off for my personal preferance. I've had the float in my toilette fail more than a few times and that has a more bouyant float, is immersed in pure cold fesh water with less mineral content, and never has algae buildup or snails, etc.

Cheers,

- Chad

Edit: photo updates on page 21

Today I met with Nate and picked up another Coralife pump from him. He was super fair to deal with and I would highly recommed him to anyone looking for equipment.

Because I don't really have any other photos, I took this one to show my topoff return line. The tubing comes up through one of the holes that I drilled for electrical cords and injects FW into the first chamber of my sump 8 times/ minute.


http://i37.photobucket.com/albums/e9.../070325009.jpg




Cheers,

- Chad

I've gone both ways and the float switch worked way better for me. I'll offer two ideas that could give you peace of mind.

1) Use two float switches for redundancy. The chances of both switches failing at the same time is pretty remote.
2) Push the water in through VERY low volume irrigation drippers. That way, the system is incapable of delivering water really fast, even if the floats fail. If the float got stuck "on", it would still take 24 hours or more of continuous pumping before the tank level would start to rise.

One question though...When you do a water change, it is only a partial volume change, right? You're not doing a 100% water change. So if your evaporative system has pumped a bit too much water in there, you will have diluted the system and will be running slightly low salinity. If you want to correct this during a water change, you'll have to adjust the salinity of your replacement SW higher to compensate.

couple comments
 

Hey, things looking great had a couple comments, sorry if I missed any of this earlier in the thread.

- how does one get in touch with Nate, where does he work?
- why did you choose to take out the bubble trap in your sump? have you any problems with the bubbles now going over the partition
- I bet at lot of us could appreciate a price breakdown of your setup

Thanks, ohh ya i'm looking forward to another tank video tour someday, hint hint, hehehe :)

Take care,
Nano

untamed,
Thanks for the info. If I ever had to switch systems to a float, I would put into practice your safety measures. I can't see that happening though.
As I said, I kept a 2gal nano for two years with one of these pumps and my salinity was always rock solid (amazing feat for a nano/pico that size). So far this one has been running for two weeks and all I have observed is the water level in my sump moving just above the line on my sump over night, and just below the line by the end of the day. I attribute this to the on/off cycle of my T5HO lighting. It is only a couple millimeters of drift and the difference in salinity is undetectable via refractometer.
I have not observed a change in evaporation rates from day to day (only the day/night cycle which seems to be self cancelling). The tank is in my basement, and the house is temperature controlled via thermostat.
Perhaps you findings are the result of the type of pump you tried to use for topoff. ???
I stayed away from peristaltic pumps when researching my topoff options because I felt that they were designed to be monitored and checked way more frequently than we usually would do topoffs by hand anyways. Also, the tubing stretches and wears as it pumps which affects the dosing rate. In hospital IV applications the tubing is swapped out so often it is baisically disposable. If you don't mind me asking, what brand of pump were you using?

nanopodreefer,
Nate can be reached via PM to "Nate". He is working for a wholesale company and can get some good prices. Also, as I found with this pump, he goes out of his way to take care of you.

Sorry dude but I'm not ready, emotionally, to add up the cost yet :razz:

- Chad

It was a Kangaroo medical peristaltic pump, so maybe it just wasn't consistent enough. I could also have been that evaporation rate in my particular home was more variable.

That's a good point too. I may have been lucky that my nano was in a large government building with air contitionioning too. ???
I bet I would see more fluctuation if my current setup was upstairs in my house where the temperature fluctuates a lot more than it does in the basement.
Thanks for the great input on float switches - I'm sure it is the best way to go in certain applications.
Cheers,

- Chad

First Corals
 

Here are a couple zoanthid colonies that I picked up. The photos are under the T5HO actinics. With the daylight bulbs they don't look nearly as nice:

http://i37.photobucket.com/albums/e9.../070409058.jpg



http://i37.photobucket.com/albums/e9.../070409039.jpg



Hope you like,

- Chad

sweet zoos. i gotta get me some o those

Thanks Justin.

Well I added 20lbs of rock to the tank. You can't see it all in the photos because I put a big piece in the sump because it had some gsp on it. (After scraping off as much as I could, I am trying to kill the rest by keeping it in the dark for a while - just so it doesn't take over my rock-work).

Hope you enjoy:



http://i37.photobucket.com/albums/e91/honda919/4.jpg




http://i37.photobucket.com/albums/e91/honda919/6.jpg


- Chad