New Tank, Lots of questions

[medievalfish]

I am waiting for my tank to cyle and have some questions. I started my cycle on 2-28 and have been taking readings regularly.
My Ammonia topped out at 1.0 on 3-3 and has sinced dropped to 0
My Nitrites topped out at 2.0 on 3-8 and has sinced dropped to 0.5
My Nitrates reached 20 on 3-8 but dropped to 10 today!?
Is it normal for the Trates to drop? There is a emerald crab smaller than a dime in the tank.(55 gallon tank)
Also, I had been using a glass drop-in Hydrometer until 3-5 when it got dropped-out. I replaced it with a plastic model with a pivoting pointer by marineland. Glass drop-in read 1.022 consistently. On 3-8 when I first tested with the plastic one, it reas 1.028. It has read 1.028 every time since. It seems odd to me that my S.G. could change over a 3 day period and then stabilize. Does anyone have experience with the plastic marineland hydrometer? Are they accurate? Which reading would you trust?

 

[earlybird]

Hydrometers are crap and known to stick and give false reads. Purchase a refractometer, that's what the pros use.

 

[keith burn]

hi, looking good only time will tell.but i thank you will love it.
imo wait for at min of 30 day befor live stock.
what did you use to cyle the 55gal ????
imo all hydrometers like that are very unaccurate...
best to get a refractometer the best way to go...

 

[medievalfish]

I started my cycle with a feeding of fish food. I had placed some LR (or so I thought, I get confused on that topic) but didn't see any resonse. The LR I had placed had been dry for some time and was white mostly. I went to the LFS and purchased some LR with growth straight out of their display tank and kept it wet until I could put it in my tank, that's when the readings really started to change.

 

[medievalfish]

I am still wondering if it normal for the Nitrates to drop without a water change on a newly cycling tank?
:thinking:

 

[geridoc]

Nitrates don't normally drop without water changes or extensive algal growth. It is more likely that you now know the reproducibility of your test kit.

 

[ruaround]

sounds like its coming along...

... you can do small water change if youd like... some people reccomend water changes during the cycle...

 

[aztec reef]

i recomend water changes during cycle anytime ammonia is present or greater that 0.5. are you sure the nitrates have gone to zero by itself. they could if you have great filtration but being a new tank i doubt it.
a waterchange never hurts :happyfish

 

[chinpokomon]

Originally Posted by medievalfish
I started my cycle with a feeding of fish food. I had placed some LR (or so I thought, I get confused on that topic) but didn't see any resonse. The LR I had placed had been dry for some time and was white mostly. I went to the LFS and purchased some LR with growth straight out of their display tank and kept it wet until I could put it in my tank, that's when the readings really started to change.

I can solve your nitrate mystery it’s the magic of fully cured mature live rock. The first rock you placed in the tank was dead it had little or none of the anaerobes necessary to finish the nitrogen cycle (Nitrocystis, Nitrococcus, Nitrospira and Nitrobacter). These guys turn your nitrate into nitrogen and oxygen gas that passes back into water. This process is done deep in the airless pores of your LR When you introduced the second batch of anaerobic bacteria laden “live’ rocks they soon consumed your excess nitrate. The Berlin system (LR, skimmer and proper light) is popular because it gives the best results with the least effort.

 

[myrtle beach]

Check to make sure there are no bubbles clinging to the pointer. Also, it should be gaged for your temp. around 78-80.

 

[spanko]

I remember reading that if you have nitrites in your tank you can get a false reading when testing nitrates.

 

[browniebuck]

Also, I had been using a glass drop-in Hydrometer until 3-5 when it got dropped-out. I replaced it with a plastic model with a pivoting pointer by marineland. Glass drop-in read 1.022 consistently. On 3-8 when I first tested with the plastic one, it reas 1.028. It has read 1.028 every time since. It seems odd to me that my S.G. could change over a 3 day period and then stabilize. Does anyone have experience with the plastic marineland hydrometer? Are they accurate? Which reading would you trust?
Have you added water to the tank to top it off? I know that when I started out, I would top off with saltwater, which caused my salinity to increase (water evaporates, salt doesn't). I am not sure, but this may be the cause of your salinity increase. If you are adding top off, use plain RO water, as it should (in theory) bring your salinity back to where you started.

 

[saltfreak4]

www.icllabs.com/hydr_hints.html
Hydrometers were tested by an independent magazine and found to be very accurate if the above parameters are met. All this hype around the refractometers is just that....hype. There is one thing that the test revealed and that was that if you are going to use the hydrometers they will need to be replaced at certain intervals (fairly short ones), and I figured I would save money with a refractometer, so that's what I went with. The glass ones are not accurate, because the gauge used to take the reading is not stable. I haven't seen studies on those, but I would guess that the glass float type was not reading correctly and your hydrometer is producing the correct reading. If you are close to a LFS they could verify that for you, if you were unsure.