I'm a TDS Meter Believer

So, I've had some time to use my TDS meter. What I found was that the output of my RO/DI unit was not the pure water I was hoping for. Instead of having a low reading, close to 0, the output was measuring anywhere from 200 down to 40ppm. The longer the RO/DI unit sat idle, the higher the reading would be. If I ran it for a long time the reading would drop.

My meter has two inputs. A slide switch selects which input is displayed on the LCD; in or out. I originally hooked it up to measure my water supply into the RO unit, municipal supply and the output out of the DI that went into my storage container. My municipal input has a TDS reading of about 300 ppm. Since I can't control it and since it doesn't need to be monitored regularly I moved the TDS in probe to measure the water out of the RO filter which feeds the input of the DI filter.

What I found was that the RO output had a TDS reading of 6 ppm. Since the DI output was varying between 200 and 40 it was obvious that the DI resin was actually contaminating the water rather than filtering it. Time to change the resin. The resin indeed was very dark but I never noticed it because the location of the filter is pretty dark.

So I ordered more resin from the Pure Water Club on eBay.This where I bought the filter 15 months ago. The refill resin arrived quickly and I replaced the resin in the two canisters. Now, my RO/DI filter produces pure water with a TDS measurement of 0 ppm.

The moral of this long-winded story is if your RO/DI filter is more than 6 months old you really should get a TDS meter to verify your water quality is what you think it is.

New Frags

I've been resisting going to the LFS for some time. I love visiting the place but if I go in I always come out with something. I decided it was time. My nitrates are at 0.5 ppm and I have new lights. I like buying frags. They sell frags for$19. If they don't make it its not the end of the world. I can buy 3 frags for what the price of one coral usually costs.

So here's what I got.

An orange (or is it red) monti cap frag. It's about 3 inches across. I was bale to wedge into this piece of LR so thats where it is going to live.

From Paul's Reef - Apr 15, 2008

and a Zoa frag. This frag is only about 2 inches across but has two different types on it.

From Paul's Reef - Apr 15, 2008

I bought a zoa rock a long time ago and it didn't do well. There are only about 4 polyps left on it. I want to see if this one does better before buying more.

Caught You

I caught the smaller of my two known Mythrax crabs that I talked about in my earlier post. I basically took the piece of live rock out that he called home, held it over my refugiuem and prodded him with some pliers until he came scooting out and dove into the fuge.

I then picked him up out of the fuge and took these pictures:

From Paul's Reef - Apr 15, 2008

From Paul's Reef - Apr 15, 2008

From Paul's Reef - Apr 15, 2008

From Paul's Reef - Apr 15, 2008

He's back in the fuge hiding under some Chaeto.

I Can See Your Beady Red Eyes

From Paul's Reef - Apr 15, 2008

I have another Mythrax crab. This one hangs out in a crevice in my live rock right in front of the tank. He is also a mason. He gathered up a bunch of live rock rubble and he uses it to wall himself off inside his crevice.

From Paul's Reef - Apr 15, 2008

I thought I had a picture of him completely walled off but I looked and can't find one. You'll have to take my word for it. I only noticed this guy originally because I saw a piece of rock wiggling. I wasn't sure what it was at first because the crab was not visible behind his wall. A few days later the top of the wall was gone and I was able to see the crab tucked away in its home.

My tank is also home to another Mythrax crab. The other one has hairy legs and probably has a leg span of about 4 inches. I need to get him out of the tank and into the fuge before he develops an appetite for corals and fish. He moves so fast that I have not been able to catch him yet. I need to implement a trap by tying a piece of shrimp to a small rock and putting it in the bottom of a small plastic container. Crabs check in but they can't check out. I may try to get this small one out sooner than later while he is still easy to catch.

Tentacle Lickin' Good

From Paul's Reef - Apr 15, 2008

I fed my Bubble Tipped Anemone a small sliver of frozen Formula One yesterday. It closed around the piece of food and ate it. When it started opening back up I was able to snap this picture of the anemone with a tentacle still in its mouth. I never really knew before how it got the food to its mouth. I always thought that the tentacles kind of pushed it in that direction until it fell in. From this picture it looks like a tentacle grabs the food and places it in the mouth.

How does it do this? This animal has no brain. How does it know the spatial relationship between its tentacles and its mouth? Simply fascinating.

Confused Clown

Every few days my BTA expels all of its water and shrinks down to nothing for an hour or so. My tomato clown doesn't seem to be too happy about this situation. It still tries to root around the deflated tentacles nonetheless and looks very confused when the anemone does this. Lucky for the clown the anemone reinflates itself rather quickly and all becomes right in the world again.

From Paul's Reef - Apr 15, 2008

TDS Meter

I purchased an HM Digital DM-1 dual in line TDS Meter from Bulk Reef Supply and received it today. A TDS meter is used t measure the amount of Total Dissolved Solids in RO/DI water. My RO meter is about 14 months old so I figured it was time to check on the performance of the filter. Since it is a dual meter it allows me to check on both the tap water and RO output. If I want I can place the first sensor between the RO and DI sections but haven't done that yet.

My water input measures 313 ppm. The output of the RO filter was measuring 60 ppm, not great when the goal is 0 ppm. I have never flushed the membrane so I went ahead and flushed it for about 45 minutes. I also positioned the two DI canisters so they are vertical instead of horizontal. This ensures that the water goes through the beeds not over them. After flushing and running the RO filter the output is now down to 8 ppm of TDS. Much much better. I did notice that the beads in the two DI filters are now dark. The second filter is much darker than the first which makes no sense to me. It's probably time to replace the resin.