Large water changes

drfu

New member
Is their any issues to doing large, say 50%, water changes to your livestock, inverts, corals if you get the Ph, temp & salinity as close as possible to your tank water? Im having a phosphate issue and want to knock it down naturally with water changes and then monitor it to see if it rises again?
 

drfu

New member
What type of water are you using? That may be the source of your Phosphates.

Rodi from a Spetrapure cspdi90, i have tested the water from it and the phosphorus in ppb are minute & 0 tds si i would have to say it was from over feeding
 

EllisJuan

New member
Gotcha. There is nothing wrong with doing big water changes. What type of rock did you use? Do you think it could be leaching phosphates? How high are they?
 

Reefer54

New member
at some point, water changes will not be able to keep up with phosphate if you do not fix the phosphate issue.

Large Water Changes, if you are going to use them as regular maintenance....temp, sg, alk, mg, cal, ph all need to be matched, as considerable shifts in those will be noticed by your corals, and it is really easy to miss the mark, causing instability or swings in the elemnts. It is also good practice if you really have to do it, to let the water "mature, season" whatever you want to call it,but fresh mixed water is fairly abrasive, which is why you see corals slime up if you do changes right in the tank and especially if you happen to toss new water diirectly on a coral. Allowing the water to create that slimy feeling in your mixing bucket is a good idea. Water changes should always be performed slowly through the sump. I like to add about a pint at a time, but do 5% changes weekly as small changes allow me to keep the params as stable as possible while also giving me time each week to really clean out doc that have settled.

i would address the phosphate introduction and not try to export it to keep up...
 

EllisJuan

New member
dont you read.....he just said overfeeding.

Nope. I just randomly click on posts, slam my fingers into the keyboard, and hit reply.

Sorry, I just usually don't associate overfeeding to high phosphates as much as high nitrates. I go through periods of pretty heavy feeding when I am trying to train fish to take prepared food and I usually don't see a spike in phosphates. That coupled with his relatively recent join date I thought the tank may be fairly new and perhaps he used rock that is know to leach phosphates. I was just trying to give him another possible source of his phosphates that may be worth considering.

Thanks for being rude and abrasive. Everyone loves being belittled when they are trying to help.
 

Randy Holmes-Farley

Reef Chemist
Premium Member
One problem with doing a big water change to drop a high phosphate level, even 100% change, is that it likely won't really drop phosphate as much as you'd like because there will be substantial phosphate attached to all of the calcium carbonate surfaces in the tank.

When you add the new water back, some of this will desorb and drive the concentration back up again. Not as high as before, but also not as low as you'd predict based on the size of the change.

So in the end, water changes may not be either the cheapest or easiest way to reduce phosphate, even in a one time spike.
 

drfu

New member
One problem with doing a big water change to drop a high phosphate level, even 100% change, is that it likely won't really drop phosphate as much as you'd like because there will be substantial phosphate attached to all of the calcium carbonate surfaces in the tank.

When you add the new water back, some of this will desorb and drive the concentration back up again. Not as high as before, but also not as low as you'd predict based on the size of the change.

So in the end, water changes may not be either the cheapest or easiest way to reduce phosphate, even in a one time spike.

Randy, do you recommend something else to lower phosphorus levels then? I can not remove the rock with the amount of corals & such already attached to them.

I am not to comcerned with the cost associated with water changes, rodi water is free and only having an 8 gallon tank will not use too much salt.
 
Last edited:

drfu

New member
Gotcha. There is nothing wrong with doing big water changes. What type of rock did you use? Do you think it could be leaching phosphates? How high are they?

If it is the rock all i can do is either water changes or some binding media as the rock can not be removed.

Im not sure what kind of rock it is, it was cured @ my lfs.

My last test w/hanna was 40 ppb phosphorus or .12 ppm of phosephate but this was a week ago so im not sure, my nitrates are around 3-5 right now as i did another 25% water change yesterday.
 

drfu

New member
at some point, water changes will not be able to keep up with phosphate if you do not fix the phosphate issue.

Large Water Changes, if you are going to use them as regular maintenance....temp, sg, alk, mg, cal, ph all need to be matched, as considerable shifts in those will be noticed by your corals, and it is really easy to miss the mark, causing instability or swings in the elemnts. It is also good practice if you really have to do it, to let the water "mature, season" whatever you want to call it,but fresh mixed water is fairly abrasive, which is why you see corals slime up if you do changes right in the tank and especially if you happen to toss new water diirectly on a coral. Allowing the water to create that slimy feeling in your mixing bucket is a good idea. Water changes should always be performed slowly through the sump. I like to add about a pint at a time, but do 5% changes weekly as small changes allow me to keep the params as stable as possible while also giving me time each week to really clean out doc that have settled.

i would address the phosphate introduction and not try to export it to keep up...

I mix my salt overnight, introduce the water through my back chamber but are you saying not to do large ones?

As per above, i match ph, temp, sg to the tank, as for Ca, Mg, Alk i do not dose with anything, just what the salt mixes in so im thinking they are a close match minus what is being consumed by the corals, etc. does that make sense or am i missing something?
 

Fishyoga

New member
Is the Phosphate test your only indication of high levels? Or are there visible tank problems?
I ask because I am currently working on a small phosphate issue in my tank. What gave it away was the development of cyano. When I do a water change, I also siphon off the surface of the sand. I use the end of the tubing to scrape off and suction up any thing that has developed on my rocks.
 

drfu

New member
Is the Phosphate test your only indication of high levels? Or are there visible tank problems?
I ask because I am currently working on a small phosphate issue in my tank. What gave it away was the development of cyano. When I do a water change, I also siphon off the surface of the sand. I use the end of the tubing to scrape off and suction up any thing that has developed on my rocks.

No i had a dino/cyno or diatom issue happening when my lights came on each day. I have been doing 25% wc & vac the sand bed to bring it down, its almost gone but my Hanna checker is still showing too high a level of phosphorus so I'm worried it will come back.
 
Top