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View Full Version : Please Help Me with my water parameters!


advocate777
02/13/2013, 03:40 PM
I started a new 75 gallon tank almost 8 weeks ago. It has live rock in it and some 'clean-up crew' which I got (live rock and clean up crew) from Tampa Bay Saltwater.

The test kit: Instant Ocean
Water: R0/DI
Salt mix: Instant Ocean

Okay, the tank cycled great. Ammonia levels have been O
Issue #1: the specific gravity/salinity (measured both by a refractometer and a typical fish store hydrometer)
A.) the Refractometer always reads lower than the Hydrometers (I actually use 2 hydrometers and they come out pretty close to one another)
For instance, on Dec. 23rd the Hydrometer read 1.023 and the Refractometer read 1.020
The salinity has steadily been rising.
Today, the Refractometer read 1.030 and the Hydrometer 1.30
Question: how do I bring the salinity down to acceptable range?

Issue #2
The ph today, measured for the first time since the tank was set up 8 weeks ago, measured under 7.8 because that is the lowest color on the scale.
The alkalinity, measured for the first time since the tank was set up today, measured 100 ppm or 5.6 Dkh
Question: how do I fix that?

Last issue:
I have a nice eheim water heater. But I have had some difficulty keeping the temperature consistent. In the last 8 weeks it has ranged between a low of 73 to a high of 81. There are glass covers on the tank top and the lights rest on that - gets hot....if I keep the heater on the tank gets to 78-80 range but if I turn off the heater it drops down to 73-75 range. I know we are looking to get a consistent range and not have daily drops of 78 to 73. Plus, the room the tank is in has inconsistent heat in that it is cold up here in Pennsylvania now and when the heat is cranking this room is toasty but when the heat is off it gets chilly - the room itself is hard to keep a consistent temperature in.
Question: any feedback would be great

Mr31415
02/13/2013, 04:19 PM
Hydrometers are notoriously inaccurate. Make sure to calibrate your refractometer using RO/DI water. Also, is your refractometer an ATC model? I.e. does it correct for temperature? 1.020 is a bit low, especially for inverts. Try to get it up to 1.025 after ensuring your test equipment is accurate.

Salinity will only rise if you do not top up with fresh water.

For a 75 gallon tank to rise from 1.020 to 1.030 in two months is alarming. Provided you are topping up with fresh water this should not change at all. If anything a tank loses salinity in time due to salt creep and skimming.

I would first get the salinity right. Then try to aim for an alkalinity of 7 - 9dKH and your pH will self correct (provided you have good ventilation in your room).

A temperature fluctuation of 73 to 81 degrees Fahrenheit is very bad. Temperature stability is key. Should try and keep it between 77 - 80. Sounds to me like your heater is set too low and the heat from the lights pushes the tank too high. You need a fan or chiller to cool it down during the day and need to set the heater to a higher value so that it does not drop below 77.