Newbie questions

[philosophile]

Hi Everyone,
I'm just starting out on my saltwater journey, I've kept freshwater for a long time.

Right now, I've got a 30 gallon, live rock, live sand, fluval G6 (yeah I'm splurging). It's been set up for about 2 days cycling.

I know that my fluval G6 measures electrical conductivity, and I'm not supposed to trust it in the first couple of days, but here's what confuses me. The manual says that I should be looking for a specific gravity reading for most saltwater set ups, between 1.0258 and 1.0275... the EC equivalent of 52-55 mS/cm That seems awfully high. My instant ocean hydrometer says I have a S.G. of 1.022... my current fluval EC reading is absurdly low, 36 (but I'm supposed to ignore it for the first few days until air bubbles are all pushed out).

But to get to my current S.G. I had to add a few cups of instant ocean to the water, since it was low.... which was really odd, since when I mixed it it, was all at 1.022. But I did mix the water cold.... the tank temp is currently 76 F. I know I'm supposed to correct for changes something like -.001 per 10 degrees up. But that means my reading should have gone up, not down, and if anything I would have added too much salt, not too little. I was tapping and there weren't any airbubbles when I mixed initially.
I know, buy a refractometer.... I will as soon as my wallet recovers from the live rock and Fluval g6.

When it comes to temp of my tank, I'm reading all sorts of crazy numbers from 82 degrees being good, to 80 being the max. I have a temperature flux between 73 degrees to up to 80 degrees (it was a hot day yesterday). I don't want to set my heater too high, and have it keep the tank at say 76 at night, and then during the day it end up cooking everything inside because the ambient temperature was 84. I plan on keeping coral (say frogspawn). My tank is uncovered with eggcrate, T5 lighting 10k and actinic.

So..... On to questions:

1. What the heck happened to my s.g.? Adding live rock? Sand?
2. How much is too much of a temperature flux?
3. What temp should I keep my tank at?

Any other advice to a novice saltwater keeper would be appreciated.

[Reefman29]

The rock and sand don't affect salt concetrations. Temperature should be between say 76 and maximum of 84 but something like 80 would be good. Temperature flux now isn't bad, but when you add fish and coral it will be. Work on adjusting things to keep the temperature stable. Advice- PATIENCE

[DylanC]

I don't have an answer to number one
but
2. a two to three degree difference isn't going to hurt a tank. if you are worried about it getting too hot add a fan blowing over the surface to help cool it down.

3. i've heard anywhere between 78 to 82 degrees for a normal temp so 80 would be a nice medium

hope i helped!

[Chris27]

78-82 is a good range, but it's definetly best to keep it as stable as possible, perhaps 80 is a reachable goal in your tank given the temperature of the house.

As for the salinity, the swing arm hydrometers are rough, they are calibrated to work at a certain temp, and even the smallest of air bubbles on the arm will throw off the measurement. My advise, take some of your water to a LFS, and have them check it with a calibrated refractometer or meter to verify your readings.

Good Luck, and enjoy the ride.

[thegrun]

1.025-1.026 is the recommended salinity level if you plan on keeping corals. 1.022 is okay if you are going fish only, but I even keep my FO tanks at 1.025 to mimic the ocean.