hard sand clumps

Your opinions please,
Shortly after my tank cycled back in april or while it was cycling my DT got a hard concrete top layer of sand maybe 1/4" to 1/2" thick, what could have caused this? I busted it up and now since Im fixing to start adding corals I am going to remove a bunch of little chunks but just wondering. My fuge didn't do this and it was the same carrib sea fiji pink sand. The only difference is the fuge had water in it when I dumped the sand in and the DT I put the sand in first then added water. I went to one LFS and they said it was the 2 1/2 to 1 ratio of recipe 1 and 2 alk and brs cal and mag I was using? The guy in the back office telling me this wouldn't come out to talk to me so I could explain to him this happend before the 2 part and the fuge didn't do it, I was going through a middle man. Of coarse he wanted me to buy a comercial 2 part at the store.
I need a couple good sand sifters in both the fuge and DT but have been going slow and haven't added them yet. I am dosing (to me) heavy with 2 part for really nothing in there, but according to the salifert kits this is my daily usage. Maybe because my coralline algea is fixing to explode (signs of this) and I started with dry rock (4/26/11) it's sucking the alk and cal up like a sponge.

DT: 75g -100lb rock -40lb sand
fuge 40g SSB
sump 16g

What I have: coral beauty, six line, 3 brittle, snails, pulsing xenia

Readings: sal 1.026, mag 1450, alk 3.1meq, cal 420

Daily usage to keep it there: 3oz recipe #1 and 7oz recipe #2 alk, this equals 6-1/2oz recipe #1 alk, equal part 6-1/2oz recipe #1 cal.

Thanks for any thoughts

 

IME sand clumping is usually from dosing too much or not slowly enough and the calcium/alkalinity is precipitating and causing the clumps. Also when you say you added the sand first then the water I am assuming you mean you mixed the saltwater in a seperate container then added it. If salt was mixed in the tank it is possible that some did precipitate out of the salt mix. If this happened before dosing started I am not sure how else it could have caused the clumping.
I am also a little confused as to why you are mixing recipes 1 and 2 for alk.

 

Yes sand first then mixed saltwater on top of the sand. I did have a problem with precipitation for awhile before I learned 2 part, now i'm manualy dripping from a wally world .99 cent ketchup bottle turned up side down with 1/4" air line run through a air valve. Dripping one drip per 3 sec., just weird only my DT did this and not my fuge and was doing it before I got into 2 part learning and getting ready for corals. Oh well, not a big deal at all, just curious.
Thanks vbb

 

Hey whatever works.;D It also wouldn't be totally unheard of for you to have gotten a bad batch of salt that had too much Calcium/Alkalinity in it.(Or not enough Magnesium to keep the Cal/Alk in solution) Good luck with those corals and don't forget pics for the picture freaks here.;D

 

Off subject i know but i wish once a yr everybody on here could get together and meet if they wanted to, a lot of good people sharing and I think meeting in person sharing stories could be a good thing. I also realize we are from everywhere
Again thanks vbb

 

Well I met Matt at Macna in Orlando along with a few other 3reefers. You should definitely check one out if it comes close to your area. Great place to meet fellow reefers and some great speakers and exhibits too.8)