The Flood Club

Brown woke up at 5:30 to go to work, as is his wont; the governor of North Carolina had closed the entire state, as is hers when there is the slightest hint of snow.  He came back to bed and we grabbed another hour of sleep until the sound of a powerhead running dry yanked us awake.

waterfall in living room


It’s… it’s not a good noise.  It’s a furious churning of gears around burbling.  It’s a darned terrifying noise when you know for a fact that the water was topped off right before you went to bed and there’s only one way the tank lost three gallons between then and now.  Yep, I thought, as the bath mat in front of the tank squished beneath me– I’ve renewed my membership in the Flood Club.

I am not, and hope to never become, a charter member of the Flood Club.  Charter members gain their ranks through catastrophic disasters.  Some jerk grabs the top of the tank and pulls it down, for example, or tosses a rock through the glass.  Sadly, I renew my membership at least once per year thanks to malfunctioning equipment.   A few months ago I paid my dues when the betta filter overflowed on the kitchen counter.  This morning, the canister filter attached to the 65G had drained a good bit of water from the tank through a slow but aggressive leak.

I cleaned up the flood, checked to make sure the leak wasn’t coming from another source, and reseated the top of the canister filter.  I’m pretty sure the leak was entirely my fault; the tank had a full cleaning yesterday and I must have gotten sloppy when I closed the top of the filter.   Still, I’m now paranoid that the filter has a crack or the rubber seal is broken, so I’m checking the darned thing a dozen times an hour.  So far so good, although I only had two gallons of fresh salt water on hand when I refilled the tank from what it lost during the flood and had to top off the rest with RO/DI water and the salinity is all screwed to heck.  At some point this weekend, I need to take the time to drive out to the store with the really good refractometer and work on getting the salinity balanced again.  Lovely.

~ by KBSpangler on February 5, 2010.

7 Responses to “The Flood Club”

  1. Your salinity isn’t screwed it’s barely off.

    Assuming a 3g total leak, with a topoff of 2g SW at the correct salinity along with ~1g total RO/DI topoff, your saliniy would barely move. Just do a weighted average.

    This assumes the total saltwater in your system is only 65g, your canister and any other equipment will also contain an extra couple of gallons, throwing this measure off even more in your favor.

    Assuming a salinity of 1.025 (fairly standard reef salininty)

    You just need to multiply the values by the weights the divide by the sum of the weights.

    62g @ 1.025, 2g @ 1.025 + 1g @ 1.000

    = ((62*1.025)+(2*1.025)+(1*1.000))/65

    = (63.55+2.05+1)/65

    = 66.6/65

    = 1.02461 SG

    That would mean that your SG is off by exactly 1.00039, which is pretty darned inconsequential 😉

    I’ve seen salinity swing a whole 1.003 in an hour without causing long term harm to fish or inverts, even SPS. It all depends on the ammount of time that the salinity changes.

    Hope this helps 😀

    • Ah, but all of this assumes the salinity was at a decent level before! I’ve got one of those swing-arm hydrometers and am forgetful about salt creep. ; ) (Very helpful information – made me feel a lot better about it!)

  2. Ahh, but you’ve fallen for a trap 😛

    Swing arm hydrometers *are* accurate if you calibrate them against either a known salinity or a properly calibrated refractometer.

    Simply take your (clean!) hydrometer, measure your SG and then draw off a sample with a pipette into a holding container to be measured by a refractometer. Then you have a known value to measure against, so if yours measures 1.025SG and the refractometer measures 1.023, then you know you need to compensate by .002SG upwards 😀

    So long as you remember to soak your hydrometer in a vinegar/water solution once every month or so to clear calcium deposits, it will ever-more be accurate. 😀

    • So… either way I’m making a trip to the store with the digital refractometer, or dropping some cash on a Vital Sine? This hobby is a money pit.

  3. even a cheap refractometer ($40 range) is good enough. The trouble wiht refractometers is that you need to calibrate them from time to time, which is a major PITA if you don’t happen to have the handy-dandy calibration standard fluid on hand.

    Heck, my local guy has an IO hydrometer, his was checked against a refractometer years ago and it was found to be within .001 of true. I checked mine against his and made a similar notation. My water checked against a refractometer comes within .0005 of the true value. That’s more than enough for a reef.

    You don’t need to worry about keeping a precicely calibrated salinity. So long as it falls between 1.022 and 1.026 you’re within norms. what’s more important is keeping that value *stable* without major spikes or drops. I shoot for a target of 1.025 on my home tank, and it never varies more than one salinity point above or below that. To this date, everything I have is growing fairly well, I’m even in the process of rescuing a badly bleached trach brain and it’s comming back strong 🙂

  4. For saltwater, specific gravity is measured in either parts per thoudsand (NaCl) or in Specific Gravity (SG)

    The problem with the former is that it is too inexact, and most commercially available electronic meters that measure in ppt (with the accuracy we need) are fairly expensive or just plain not suitable for aquarium use (most inappropriate meters use a form of conductivity test which puts unwaned electrical current into the aquarium)

    SG (specific gravity) is the good old standby, as it is fairly accurately measured by swing-arm type hydrometers – provided that they are properly calibrated.

    The issue with swing arm hydrometers is that they measure density, which can be affected by *all* disolved solids in water. this isn’t generally an issue until you get into certain salt mix brands that have drastically different levels of Calcium and Carbonate additives, which can raise or lower SG by as much as .001 (or so i am told).

    The most accurate affordable method for measuring salinity for most people is a refractometer, but as above, calibrating them can be a pain, they also need to respond to a certain thermal curve.

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