I never quite experimenting and designing. Over my time spent modding carts and such I have come to a few definitive facts regarding cart mods. They all have drawbacks, you just need to know which fits you best.
I am going to start with a basic principal of fluidics, surface tension.
Surface tension and vacuum are primary reasons you can put a straw in a liquid, cover the exposed end of the straw, and lift the straw out of the liquid while keeping it full. When you remove your finger, you lose vacuum, thus the liquid falls back out of the straw.
Creating a sealing area of the liquid within a cart is key to maximize fluid delivery. We use absorptive materials within a cart to hold fluid. The more absorptive they are, typically, they have a higher retention coefficient. This means the more the soak in, the less they will let go.
To make a good cart, we have to look at surface tension. Inserting any of these materials does two things. They help support the weight of the fluid, and they reduce surface area exposed which strengthens retention.
Lets take a 2 liter bottle, fill it with water, then submerse it in water. Flip it over (top down) and lift it out. The bottle stays full until the top comes out of the water, it then chugs and comes out. As water comes out, air needs to enter to negate the vacuum.
A straw will hold the water, but the bottle will not. This is due to the ratio of weight to surface area of exposed liquid which effects surface tension.
Due to this principal, we only need to increase surface tension so a full cart (liquid, no filler) so it does not dump the fluid freely. A thin piece of foam material at the opening of the cart will help hold weight of the fluid and reduce surface volume, thus increasing surface tension. The less absorptive the material, the more it will release. Under the best circumstances, this is what we want.
When using the blue foam plug method (see ehiem filter mod) and no spring (just a plug), you can fill your cart with juice and cap it with this plug. Turning it over results in no loss of fluid.
I am going to start with a basic principal of fluidics, surface tension.
Surface tension and vacuum are primary reasons you can put a straw in a liquid, cover the exposed end of the straw, and lift the straw out of the liquid while keeping it full. When you remove your finger, you lose vacuum, thus the liquid falls back out of the straw.
Creating a sealing area of the liquid within a cart is key to maximize fluid delivery. We use absorptive materials within a cart to hold fluid. The more absorptive they are, typically, they have a higher retention coefficient. This means the more the soak in, the less they will let go.
To make a good cart, we have to look at surface tension. Inserting any of these materials does two things. They help support the weight of the fluid, and they reduce surface area exposed which strengthens retention.
Lets take a 2 liter bottle, fill it with water, then submerse it in water. Flip it over (top down) and lift it out. The bottle stays full until the top comes out of the water, it then chugs and comes out. As water comes out, air needs to enter to negate the vacuum.
A straw will hold the water, but the bottle will not. This is due to the ratio of weight to surface area of exposed liquid which effects surface tension.
Due to this principal, we only need to increase surface tension so a full cart (liquid, no filler) so it does not dump the fluid freely. A thin piece of foam material at the opening of the cart will help hold weight of the fluid and reduce surface volume, thus increasing surface tension. The less absorptive the material, the more it will release. Under the best circumstances, this is what we want.
When using the blue foam plug method (see ehiem filter mod) and no spring (just a plug), you can fill your cart with juice and cap it with this plug. Turning it over results in no loss of fluid.
I've just been using the straw method with my 510 and dripping with my Prodigy. Bought some prefilled PTB carts but haven't tried them yet. So far the straw seems to be working ok and it's not much hassle. But I am always interested in any new info if it makes sense and works.
