Help working out salinity maths

[Tiffany]

If I have a 1 litre bottle at the s.grav. of 1.025 and want to drop it to 1.009 for hypo how much fresh water needs to be added to the bottle?
My hydrometer only goes to 1.010, and the Q/T is only 42 litres. so water changes would be a litre or 2 a week..

 

[rachyl756]

If I have a 1 litre bottle at the s.grav. of 1.025 and want to drop it to 1.009 for hypo how much fresh water needs to be added to the bottle?
My hydrometer only goes to 1.010, and the Q/T is only 42 litres. so water changes would be a litre or 2 a week..

So you have 1l of 1.025. assuming your freshwater is 1.0000 you'd have

(1*1.025 +x*1.0000) / (1+x) = 1.009

x will result in liters ad if the 'fresh' water isn't 1, the 1.0 should just be changed to whatever it is.

right?

PS its 7:30 and I'm about to shop all day in chaos so all math from me should be taken with a serious second thought, but it should be right, that work, I know the units work so x will pop out in liters.

Rachel

 

[Tiffany]

Thanks Rachel
If I want to reduce the s.grav. by .005 a day after that what would be the amount of fresh water added per litre? :?:
I don't know the grav. of the fresh water unfortunately...

 

[rachyl756]

I'd say set up a drip and use your hydrometer up to where it stops being usable.

if the drip is to fast alternate how often the drip is on, if it seems to slow every so often just add a little more.

Specific gravity and I are not friends right now I only have a stupid plastic gage and nearly had a heart attack when I went to check the tank after shiopping and the thing stayed leveled out at the bottom ... then I noticed last person to use it evidently left salt water in it so it was caked to the bottom

Seriously though i do think the drip method of just watching it would be better since you want to do it gradual.between how things evaporate and everything else that can go on, that would probably give you the best results

Rachel

and yes I survived shopping this morning

 

[Tiffany]

Thanks
How did the shopping go?? Did you get yourself something? I always end up with another pair of shoes..(Madame Marcos here...Heh)
I was thinking for the Q/T, my hydrometer only goes down to 1.010. But I'll make an educated guess, I bought a cleaner wrasse and he's been in Q/T since day 1 and has ich and I've tried tri-sulfate to no avail and then increased the temp to 30deg in hypo and wanted to drop the salinity daily to try save him, as the ich is persistent, though not bad.....I'll go for 1/2 cup a day of fresh.. and see how it goes. If all else fails the copper will be added.
I've beaten it before and shall do so again.
Thanks again for your help, and remember the golden rule of shopping, boxing day sales.. Well in Oz anyway. So we always have a good time then.

 

[rachyl756]

Most of my tank is LR and corals and inverts (I have a whole 7 fish and 6 are green chromis)

we're doing a more fish tank downstairs but thats not until after the contractors finish the basement (which is the big hold up on the baby's room)

I did good shopping, got some of the fisher price aquarium seris stuff on sale Need to get everything to make a salt water fish mural on the wall, but got more shopping accomplished this morning than I thought I would. Time for trip 2 ... AND I got a surprise present from my husband last night. You know thanksgiving went poorly when you stop on the way home on a 4 hour drive and you get the really nice red mushrooms you had wanted ... and your husband that bought them doesn't -like- mushrooms

Mushrooms see to thrive so well in my tank though, I'm excited for them to get big.

Rachel

 

[Tiffany]

Well you know you're safe with chomis and they school really nicely.
It's lovely that your hubby bought you something he doesn't like, mine do well too, in some tanks they do and others they don't I guess we're lucky.
I was going to do a mosaic on the hood of the tank until I changed lighting and don't need it/can't fit it on, and am now concidering doing one around the "band" of the tank.
I got some really nice pics of some that I was going to adapt to my humble abilities!!
Have you decided what to paint? Here's some of the ones I liked, you might like to adapt them or use them, although I'm sure that you have wonderful ideas already.

 

[Tiffany]

This is the full uncropped version.
Complicated, but I love a challenge.
Contractors are always running late, and leave a mess when they leave,(note to any contracts viewing, we really do like you.......) my mothers the renovators dream, and I understand what you're going through, when it's done you'll be really happy and the stress will be worth it.

 

[Anonymous]

>... (1*1.025 +x*1.0000) / (1+x) = 1.009

The formula looks good theoretically, so for most purposes, it is sufficient. However, I just want to point out that the difference between specific gravity and density of water can make the solved value (for x) to be off a little bit.